Download Anna University B-Tech 1st Year First Year BS8161 Chemistry Lab Manual Question Paper

Download Anna University B.Tech/BE (Bachelor of Technology) 1st Year (First Year) First Year BS8161 Chemistry Lab Manual Question Paper.

?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
FirstRanker.com - FirstRanker's Choice



?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
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?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





FirstRanker.com - FirstRanker's Choice



?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





3


PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)
1. Fundamentals
To provide students with a solid foundation in Mathematics, Science and fundamentals of engineering,
enabling them to apply, to find solutions for engineering problems and use this knowledge to acquire higher
education
2. Core Competence
To train the students in chemistry practicals so that they apply their knowledge and training to compare,
and to analyze various engineering industrial problems to find solutions
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice this enables
them to find solutions for the real time problems in industry, and to design products
4. Professionalism
To inculcate professional and effective communication skills, leadership qualities and team spirit in the
students to make them multi-faceted personalities and develop their ability to relate engineering issues to
broader social context
5. Lifelong Learning/Ethics
To demonstrate and practice ethical and professional responsibilities in the industry and society in the
large, through commitment and lifelong learning needed for successful professional career






FirstRanker.com - FirstRanker's Choice



?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





3


PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)
1. Fundamentals
To provide students with a solid foundation in Mathematics, Science and fundamentals of engineering,
enabling them to apply, to find solutions for engineering problems and use this knowledge to acquire higher
education
2. Core Competence
To train the students in chemistry practicals so that they apply their knowledge and training to compare,
and to analyze various engineering industrial problems to find solutions
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice this enables
them to find solutions for the real time problems in industry, and to design products
4. Professionalism
To inculcate professional and effective communication skills, leadership qualities and team spirit in the
students to make them multi-faceted personalities and develop their ability to relate engineering issues to
broader social context
5. Lifelong Learning/Ethics
To demonstrate and practice ethical and professional responsibilities in the industry and society in the
large, through commitment and lifelong learning needed for successful professional career






4


PROGRAMME OUTCOMES (POs)
To demonstrate and apply knowledge of Mathematics, Science and engineering fundamentals in the following
experiments.
1 .To estimate HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. To determine total, temporary & permanent hardness of water by EDTA method.
3. To determine DO content of water sample by Winkler?s method.
4. To determine chloride content of water sample by Argentometric method.
5. To estimate copper content of the given solution by Iodometry.
6. To determine strength of given hydrochloric acid using pH meter.
7. To determine strength of acids in a mixture of acids using conductivity meter.
8. To determine iron content of the given solution using potentiometer.
9. To estimate iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. To estimate sodium and potassium present in water using flame photometer.
11. To determine molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. To determine Pseudo first order kinetics ? ester hydrolysis.
13. To determine Corrosion experiment ? weight loss method.
14. To estimate CMC.
15. To estimate Phase change in a solid.
16. To determine strength of strong acid vs strong base using conductivity meter.











FirstRanker.com - FirstRanker's Choice



?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





3


PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)
1. Fundamentals
To provide students with a solid foundation in Mathematics, Science and fundamentals of engineering,
enabling them to apply, to find solutions for engineering problems and use this knowledge to acquire higher
education
2. Core Competence
To train the students in chemistry practicals so that they apply their knowledge and training to compare,
and to analyze various engineering industrial problems to find solutions
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice this enables
them to find solutions for the real time problems in industry, and to design products
4. Professionalism
To inculcate professional and effective communication skills, leadership qualities and team spirit in the
students to make them multi-faceted personalities and develop their ability to relate engineering issues to
broader social context
5. Lifelong Learning/Ethics
To demonstrate and practice ethical and professional responsibilities in the industry and society in the
large, through commitment and lifelong learning needed for successful professional career






4


PROGRAMME OUTCOMES (POs)
To demonstrate and apply knowledge of Mathematics, Science and engineering fundamentals in the following
experiments.
1 .To estimate HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. To determine total, temporary & permanent hardness of water by EDTA method.
3. To determine DO content of water sample by Winkler?s method.
4. To determine chloride content of water sample by Argentometric method.
5. To estimate copper content of the given solution by Iodometry.
6. To determine strength of given hydrochloric acid using pH meter.
7. To determine strength of acids in a mixture of acids using conductivity meter.
8. To determine iron content of the given solution using potentiometer.
9. To estimate iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. To estimate sodium and potassium present in water using flame photometer.
11. To determine molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. To determine Pseudo first order kinetics ? ester hydrolysis.
13. To determine Corrosion experiment ? weight loss method.
14. To estimate CMC.
15. To estimate Phase change in a solid.
16. To determine strength of strong acid vs strong base using conductivity meter.











5

BS8161 - CHEMISTRY LABORATORY
SYLLABUS


? To make the student to acquire practical skills in the determination of water quality
parameters through volumetric and instrumental analysis.

? ???? ??? ???? ?? ???? ? ? ?To acquaint the students with the determination of molecular weight of a polymer by
viscometery.

LIST OF EXPERIMENTS:
1. Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. Determination of total, temporary & permanent hardness of water by EDTA method.
3. Determination of DO content of water sample by Winkler?s method.
4. Determination of chloride content of water sample by Argentometric method.
5. Estimation of copper content of the given solution by Iodometry.
6. Determination of strength of given hydrochloric acid using pH meter.
7. Determination of strength of acids in a mixture of acids using conductivity meter.
8. Estimation of iron content of the given solution using potentiometer.
9. Estimation of iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. Estimation of sodium and potassium present in water using flame photometer.
11. Determination of molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. Pseudo first order kinetics ? ester hydrolysis.
13. Corrosion experiment ? weight loss method.
14. Determination of CMC.
15. Phase change in a solid.
16. Conductometric titration of strong acid vs strong base.




? The students will be outfitted with hands-on knowledge in the quantitative chemical
analysis of water quality related parameters.
COURSE OBJECTIVES
COURSE OUTCOMES
FirstRanker.com - FirstRanker's Choice



?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





3


PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)
1. Fundamentals
To provide students with a solid foundation in Mathematics, Science and fundamentals of engineering,
enabling them to apply, to find solutions for engineering problems and use this knowledge to acquire higher
education
2. Core Competence
To train the students in chemistry practicals so that they apply their knowledge and training to compare,
and to analyze various engineering industrial problems to find solutions
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice this enables
them to find solutions for the real time problems in industry, and to design products
4. Professionalism
To inculcate professional and effective communication skills, leadership qualities and team spirit in the
students to make them multi-faceted personalities and develop their ability to relate engineering issues to
broader social context
5. Lifelong Learning/Ethics
To demonstrate and practice ethical and professional responsibilities in the industry and society in the
large, through commitment and lifelong learning needed for successful professional career






4


PROGRAMME OUTCOMES (POs)
To demonstrate and apply knowledge of Mathematics, Science and engineering fundamentals in the following
experiments.
1 .To estimate HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. To determine total, temporary & permanent hardness of water by EDTA method.
3. To determine DO content of water sample by Winkler?s method.
4. To determine chloride content of water sample by Argentometric method.
5. To estimate copper content of the given solution by Iodometry.
6. To determine strength of given hydrochloric acid using pH meter.
7. To determine strength of acids in a mixture of acids using conductivity meter.
8. To determine iron content of the given solution using potentiometer.
9. To estimate iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. To estimate sodium and potassium present in water using flame photometer.
11. To determine molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. To determine Pseudo first order kinetics ? ester hydrolysis.
13. To determine Corrosion experiment ? weight loss method.
14. To estimate CMC.
15. To estimate Phase change in a solid.
16. To determine strength of strong acid vs strong base using conductivity meter.











5

BS8161 - CHEMISTRY LABORATORY
SYLLABUS


? To make the student to acquire practical skills in the determination of water quality
parameters through volumetric and instrumental analysis.

? ???? ??? ???? ?? ???? ? ? ?To acquaint the students with the determination of molecular weight of a polymer by
viscometery.

LIST OF EXPERIMENTS:
1. Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. Determination of total, temporary & permanent hardness of water by EDTA method.
3. Determination of DO content of water sample by Winkler?s method.
4. Determination of chloride content of water sample by Argentometric method.
5. Estimation of copper content of the given solution by Iodometry.
6. Determination of strength of given hydrochloric acid using pH meter.
7. Determination of strength of acids in a mixture of acids using conductivity meter.
8. Estimation of iron content of the given solution using potentiometer.
9. Estimation of iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. Estimation of sodium and potassium present in water using flame photometer.
11. Determination of molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. Pseudo first order kinetics ? ester hydrolysis.
13. Corrosion experiment ? weight loss method.
14. Determination of CMC.
15. Phase change in a solid.
16. Conductometric titration of strong acid vs strong base.




? The students will be outfitted with hands-on knowledge in the quantitative chemical
analysis of water quality related parameters.
COURSE OBJECTIVES
COURSE OUTCOMES
6


INDEX [ SEMESTER ? I ]


S.No.



Date


Experiment

Date of
submission



Mark


Signature

1.

Estimation of HCl using Na 2CO 3 as
primary standard and Determination of
alkalinity in water sample.



2.


Determination of total, temporary &
permanent hardness of water by EDTA
method.



3.


Determination of chloride content of water
sample by argentometric method.



4.


Determination of strength of given
hydrochloric acid using pH meter.



5.


Determination of strength of acids in a
mixture of acids using conductivity meter.



6.


Estimation of iron content of the given
solution using potentiometer.



7.





Conductometric titration of strong acid Vs
strong base.



8.



Estimation of copper content of the given
solution by Iodometry


9.
Estimation of sodium and potassium
present in water using flame photometer




FirstRanker.com - FirstRanker's Choice



?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





3


PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)
1. Fundamentals
To provide students with a solid foundation in Mathematics, Science and fundamentals of engineering,
enabling them to apply, to find solutions for engineering problems and use this knowledge to acquire higher
education
2. Core Competence
To train the students in chemistry practicals so that they apply their knowledge and training to compare,
and to analyze various engineering industrial problems to find solutions
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice this enables
them to find solutions for the real time problems in industry, and to design products
4. Professionalism
To inculcate professional and effective communication skills, leadership qualities and team spirit in the
students to make them multi-faceted personalities and develop their ability to relate engineering issues to
broader social context
5. Lifelong Learning/Ethics
To demonstrate and practice ethical and professional responsibilities in the industry and society in the
large, through commitment and lifelong learning needed for successful professional career






4


PROGRAMME OUTCOMES (POs)
To demonstrate and apply knowledge of Mathematics, Science and engineering fundamentals in the following
experiments.
1 .To estimate HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. To determine total, temporary & permanent hardness of water by EDTA method.
3. To determine DO content of water sample by Winkler?s method.
4. To determine chloride content of water sample by Argentometric method.
5. To estimate copper content of the given solution by Iodometry.
6. To determine strength of given hydrochloric acid using pH meter.
7. To determine strength of acids in a mixture of acids using conductivity meter.
8. To determine iron content of the given solution using potentiometer.
9. To estimate iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. To estimate sodium and potassium present in water using flame photometer.
11. To determine molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. To determine Pseudo first order kinetics ? ester hydrolysis.
13. To determine Corrosion experiment ? weight loss method.
14. To estimate CMC.
15. To estimate Phase change in a solid.
16. To determine strength of strong acid vs strong base using conductivity meter.











5

BS8161 - CHEMISTRY LABORATORY
SYLLABUS


? To make the student to acquire practical skills in the determination of water quality
parameters through volumetric and instrumental analysis.

? ???? ??? ???? ?? ???? ? ? ?To acquaint the students with the determination of molecular weight of a polymer by
viscometery.

LIST OF EXPERIMENTS:
1. Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. Determination of total, temporary & permanent hardness of water by EDTA method.
3. Determination of DO content of water sample by Winkler?s method.
4. Determination of chloride content of water sample by Argentometric method.
5. Estimation of copper content of the given solution by Iodometry.
6. Determination of strength of given hydrochloric acid using pH meter.
7. Determination of strength of acids in a mixture of acids using conductivity meter.
8. Estimation of iron content of the given solution using potentiometer.
9. Estimation of iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. Estimation of sodium and potassium present in water using flame photometer.
11. Determination of molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. Pseudo first order kinetics ? ester hydrolysis.
13. Corrosion experiment ? weight loss method.
14. Determination of CMC.
15. Phase change in a solid.
16. Conductometric titration of strong acid vs strong base.




? The students will be outfitted with hands-on knowledge in the quantitative chemical
analysis of water quality related parameters.
COURSE OBJECTIVES
COURSE OUTCOMES
6


INDEX [ SEMESTER ? I ]


S.No.



Date


Experiment

Date of
submission



Mark


Signature

1.

Estimation of HCl using Na 2CO 3 as
primary standard and Determination of
alkalinity in water sample.



2.


Determination of total, temporary &
permanent hardness of water by EDTA
method.



3.


Determination of chloride content of water
sample by argentometric method.



4.


Determination of strength of given
hydrochloric acid using pH meter.



5.


Determination of strength of acids in a
mixture of acids using conductivity meter.



6.


Estimation of iron content of the given
solution using potentiometer.



7.





Conductometric titration of strong acid Vs
strong base.



8.



Estimation of copper content of the given
solution by Iodometry


9.
Estimation of sodium and potassium
present in water using flame photometer




7




CONTENTS


S.No.


NAME OF EXPERIMENT

PAGE
No.
SEMESTER - I
1.
Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in
water sample.
09
2. Determination of total, temporary & permanent hardness of water by EDTA method. 15
3. Determination of chloride content of water sample by Argentometric method. 21
4. Determination of strength of given hydrochloric acid using pH meter. 25
5. Determination of strength of acids in a mixture of acids using conductivity meter. 29
6. Estimation of iron content of the given solution using potentiometer. 33
7. Conductometric titration of strong acid Vs strong base.

39


42

8


Estimation of copper content of the given solution by Iodometry 43
9 Estimation of sodium and potassium present in water using flame photometer 47






FirstRanker.com - FirstRanker's Choice



?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





3


PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)
1. Fundamentals
To provide students with a solid foundation in Mathematics, Science and fundamentals of engineering,
enabling them to apply, to find solutions for engineering problems and use this knowledge to acquire higher
education
2. Core Competence
To train the students in chemistry practicals so that they apply their knowledge and training to compare,
and to analyze various engineering industrial problems to find solutions
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice this enables
them to find solutions for the real time problems in industry, and to design products
4. Professionalism
To inculcate professional and effective communication skills, leadership qualities and team spirit in the
students to make them multi-faceted personalities and develop their ability to relate engineering issues to
broader social context
5. Lifelong Learning/Ethics
To demonstrate and practice ethical and professional responsibilities in the industry and society in the
large, through commitment and lifelong learning needed for successful professional career






4


PROGRAMME OUTCOMES (POs)
To demonstrate and apply knowledge of Mathematics, Science and engineering fundamentals in the following
experiments.
1 .To estimate HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. To determine total, temporary & permanent hardness of water by EDTA method.
3. To determine DO content of water sample by Winkler?s method.
4. To determine chloride content of water sample by Argentometric method.
5. To estimate copper content of the given solution by Iodometry.
6. To determine strength of given hydrochloric acid using pH meter.
7. To determine strength of acids in a mixture of acids using conductivity meter.
8. To determine iron content of the given solution using potentiometer.
9. To estimate iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. To estimate sodium and potassium present in water using flame photometer.
11. To determine molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. To determine Pseudo first order kinetics ? ester hydrolysis.
13. To determine Corrosion experiment ? weight loss method.
14. To estimate CMC.
15. To estimate Phase change in a solid.
16. To determine strength of strong acid vs strong base using conductivity meter.











5

BS8161 - CHEMISTRY LABORATORY
SYLLABUS


? To make the student to acquire practical skills in the determination of water quality
parameters through volumetric and instrumental analysis.

? ???? ??? ???? ?? ???? ? ? ?To acquaint the students with the determination of molecular weight of a polymer by
viscometery.

LIST OF EXPERIMENTS:
1. Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. Determination of total, temporary & permanent hardness of water by EDTA method.
3. Determination of DO content of water sample by Winkler?s method.
4. Determination of chloride content of water sample by Argentometric method.
5. Estimation of copper content of the given solution by Iodometry.
6. Determination of strength of given hydrochloric acid using pH meter.
7. Determination of strength of acids in a mixture of acids using conductivity meter.
8. Estimation of iron content of the given solution using potentiometer.
9. Estimation of iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. Estimation of sodium and potassium present in water using flame photometer.
11. Determination of molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. Pseudo first order kinetics ? ester hydrolysis.
13. Corrosion experiment ? weight loss method.
14. Determination of CMC.
15. Phase change in a solid.
16. Conductometric titration of strong acid vs strong base.




? The students will be outfitted with hands-on knowledge in the quantitative chemical
analysis of water quality related parameters.
COURSE OBJECTIVES
COURSE OUTCOMES
6


INDEX [ SEMESTER ? I ]


S.No.



Date


Experiment

Date of
submission



Mark


Signature

1.

Estimation of HCl using Na 2CO 3 as
primary standard and Determination of
alkalinity in water sample.



2.


Determination of total, temporary &
permanent hardness of water by EDTA
method.



3.


Determination of chloride content of water
sample by argentometric method.



4.


Determination of strength of given
hydrochloric acid using pH meter.



5.


Determination of strength of acids in a
mixture of acids using conductivity meter.



6.


Estimation of iron content of the given
solution using potentiometer.



7.





Conductometric titration of strong acid Vs
strong base.



8.



Estimation of copper content of the given
solution by Iodometry


9.
Estimation of sodium and potassium
present in water using flame photometer




7




CONTENTS


S.No.


NAME OF EXPERIMENT

PAGE
No.
SEMESTER - I
1.
Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in
water sample.
09
2. Determination of total, temporary & permanent hardness of water by EDTA method. 15
3. Determination of chloride content of water sample by Argentometric method. 21
4. Determination of strength of given hydrochloric acid using pH meter. 25
5. Determination of strength of acids in a mixture of acids using conductivity meter. 29
6. Estimation of iron content of the given solution using potentiometer. 33
7. Conductometric titration of strong acid Vs strong base.

39


42

8


Estimation of copper content of the given solution by Iodometry 43
9 Estimation of sodium and potassium present in water using flame photometer 47






8



SHORT PROCEDURE:

CONTENTS
TITRATION
Estimation of alkalinity in water sample
(Std HCl Vs water sample)

Burette solution

Std. HCl


Pipette solution

Water sample


Indicator


(i) Phenolphthalein
(ii) Methyl orange


End point

(i) Disappearance of pink colour
(ii) Appearance of reddish orange colour






Relationship
between P &M
Nature of alkalinity
Amount of individual
alkalinities
OH
-
HCO 3
-


CO 3
2-

P = M

only OH
-

P or M

?
0.0

0.0


2P = M

only CO 3
2-


2P or M


0.0


0.0


?

P =0, M?0

only HCO 3
-



M



0.0



?

0.0


2P > M


OH
-
&CO 3
2-


OH
-
= 2P-M
CO 3
2-
= 2(M-P)


?

0.0

?

P < ? M




HCO 3
-
&CO 3
2-


HCO 3
-
= M-2P
CO 3
2-
= 2P

0.0 ? ?




FirstRanker.com - FirstRanker's Choice



?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





3


PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)
1. Fundamentals
To provide students with a solid foundation in Mathematics, Science and fundamentals of engineering,
enabling them to apply, to find solutions for engineering problems and use this knowledge to acquire higher
education
2. Core Competence
To train the students in chemistry practicals so that they apply their knowledge and training to compare,
and to analyze various engineering industrial problems to find solutions
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice this enables
them to find solutions for the real time problems in industry, and to design products
4. Professionalism
To inculcate professional and effective communication skills, leadership qualities and team spirit in the
students to make them multi-faceted personalities and develop their ability to relate engineering issues to
broader social context
5. Lifelong Learning/Ethics
To demonstrate and practice ethical and professional responsibilities in the industry and society in the
large, through commitment and lifelong learning needed for successful professional career






4


PROGRAMME OUTCOMES (POs)
To demonstrate and apply knowledge of Mathematics, Science and engineering fundamentals in the following
experiments.
1 .To estimate HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. To determine total, temporary & permanent hardness of water by EDTA method.
3. To determine DO content of water sample by Winkler?s method.
4. To determine chloride content of water sample by Argentometric method.
5. To estimate copper content of the given solution by Iodometry.
6. To determine strength of given hydrochloric acid using pH meter.
7. To determine strength of acids in a mixture of acids using conductivity meter.
8. To determine iron content of the given solution using potentiometer.
9. To estimate iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. To estimate sodium and potassium present in water using flame photometer.
11. To determine molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. To determine Pseudo first order kinetics ? ester hydrolysis.
13. To determine Corrosion experiment ? weight loss method.
14. To estimate CMC.
15. To estimate Phase change in a solid.
16. To determine strength of strong acid vs strong base using conductivity meter.











5

BS8161 - CHEMISTRY LABORATORY
SYLLABUS


? To make the student to acquire practical skills in the determination of water quality
parameters through volumetric and instrumental analysis.

? ???? ??? ???? ?? ???? ? ? ?To acquaint the students with the determination of molecular weight of a polymer by
viscometery.

LIST OF EXPERIMENTS:
1. Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. Determination of total, temporary & permanent hardness of water by EDTA method.
3. Determination of DO content of water sample by Winkler?s method.
4. Determination of chloride content of water sample by Argentometric method.
5. Estimation of copper content of the given solution by Iodometry.
6. Determination of strength of given hydrochloric acid using pH meter.
7. Determination of strength of acids in a mixture of acids using conductivity meter.
8. Estimation of iron content of the given solution using potentiometer.
9. Estimation of iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. Estimation of sodium and potassium present in water using flame photometer.
11. Determination of molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. Pseudo first order kinetics ? ester hydrolysis.
13. Corrosion experiment ? weight loss method.
14. Determination of CMC.
15. Phase change in a solid.
16. Conductometric titration of strong acid vs strong base.




? The students will be outfitted with hands-on knowledge in the quantitative chemical
analysis of water quality related parameters.
COURSE OBJECTIVES
COURSE OUTCOMES
6


INDEX [ SEMESTER ? I ]


S.No.



Date


Experiment

Date of
submission



Mark


Signature

1.

Estimation of HCl using Na 2CO 3 as
primary standard and Determination of
alkalinity in water sample.



2.


Determination of total, temporary &
permanent hardness of water by EDTA
method.



3.


Determination of chloride content of water
sample by argentometric method.



4.


Determination of strength of given
hydrochloric acid using pH meter.



5.


Determination of strength of acids in a
mixture of acids using conductivity meter.



6.


Estimation of iron content of the given
solution using potentiometer.



7.





Conductometric titration of strong acid Vs
strong base.



8.



Estimation of copper content of the given
solution by Iodometry


9.
Estimation of sodium and potassium
present in water using flame photometer




7




CONTENTS


S.No.


NAME OF EXPERIMENT

PAGE
No.
SEMESTER - I
1.
Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in
water sample.
09
2. Determination of total, temporary & permanent hardness of water by EDTA method. 15
3. Determination of chloride content of water sample by Argentometric method. 21
4. Determination of strength of given hydrochloric acid using pH meter. 25
5. Determination of strength of acids in a mixture of acids using conductivity meter. 29
6. Estimation of iron content of the given solution using potentiometer. 33
7. Conductometric titration of strong acid Vs strong base.

39


42

8


Estimation of copper content of the given solution by Iodometry 43
9 Estimation of sodium and potassium present in water using flame photometer 47






8



SHORT PROCEDURE:

CONTENTS
TITRATION
Estimation of alkalinity in water sample
(Std HCl Vs water sample)

Burette solution

Std. HCl


Pipette solution

Water sample


Indicator


(i) Phenolphthalein
(ii) Methyl orange


End point

(i) Disappearance of pink colour
(ii) Appearance of reddish orange colour






Relationship
between P &M
Nature of alkalinity
Amount of individual
alkalinities
OH
-
HCO 3
-


CO 3
2-

P = M

only OH
-

P or M

?
0.0

0.0


2P = M

only CO 3
2-


2P or M


0.0


0.0


?

P =0, M?0

only HCO 3
-



M



0.0



?

0.0


2P > M


OH
-
&CO 3
2-


OH
-
= 2P-M
CO 3
2-
= 2(M-P)


?

0.0

?

P < ? M




HCO 3
-
&CO 3
2-


HCO 3
-
= M-2P
CO 3
2-
= 2P

0.0 ? ?




9





Expt. No. 1 DETERMINATION OF ALKALINITY IN WATER
AIM
To determine the type and amounts of alkalinity in the given water sample. A standard solution of Na 2CO 3
of strength ____N is given.

PRINCIPLE
Alkalinity in water is due to the presence of soluble hydroxides, bicarbonates and carbonates.
Determination of various types and amounts of alkalinity is easily carried out by titration with standard HCl
employing the indicators phenolphthalein and methyl orange independently or in succession.

The following reactions occur when different types of alkalinity are neutralized with acid.

OH
?
+ H
+
? H 2O completed at pH 8.2-9.0 ----- (1)

CO 3
2 ?
+ H
+
? HCO 3
?
----- (2)

HCO 3
?
+ H
+
? (H 2CO 3) ? H 2O + CO 2, completed at pH 4.2-5.5 ----- (3)

Neutralisation (1) & (2) will be notified by phenolphthalein end-point while all the three will be

accounted by
methyl orange end-point. Bicarbonate in eqn. (3) may be due to the existence of soluble free bicarbonate salts and
bicarbonates resulting from half neutralization of soluble carbonates (eqn. (2))

Various steps to be followed

a) A known volume of water sample is titrated against std. HCl using first phenolphthalein indicator till
end-point (P) and the titration is continued without break using methyl orange indicator till the end-
point (M).



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?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





3


PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)
1. Fundamentals
To provide students with a solid foundation in Mathematics, Science and fundamentals of engineering,
enabling them to apply, to find solutions for engineering problems and use this knowledge to acquire higher
education
2. Core Competence
To train the students in chemistry practicals so that they apply their knowledge and training to compare,
and to analyze various engineering industrial problems to find solutions
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice this enables
them to find solutions for the real time problems in industry, and to design products
4. Professionalism
To inculcate professional and effective communication skills, leadership qualities and team spirit in the
students to make them multi-faceted personalities and develop their ability to relate engineering issues to
broader social context
5. Lifelong Learning/Ethics
To demonstrate and practice ethical and professional responsibilities in the industry and society in the
large, through commitment and lifelong learning needed for successful professional career






4


PROGRAMME OUTCOMES (POs)
To demonstrate and apply knowledge of Mathematics, Science and engineering fundamentals in the following
experiments.
1 .To estimate HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. To determine total, temporary & permanent hardness of water by EDTA method.
3. To determine DO content of water sample by Winkler?s method.
4. To determine chloride content of water sample by Argentometric method.
5. To estimate copper content of the given solution by Iodometry.
6. To determine strength of given hydrochloric acid using pH meter.
7. To determine strength of acids in a mixture of acids using conductivity meter.
8. To determine iron content of the given solution using potentiometer.
9. To estimate iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. To estimate sodium and potassium present in water using flame photometer.
11. To determine molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. To determine Pseudo first order kinetics ? ester hydrolysis.
13. To determine Corrosion experiment ? weight loss method.
14. To estimate CMC.
15. To estimate Phase change in a solid.
16. To determine strength of strong acid vs strong base using conductivity meter.











5

BS8161 - CHEMISTRY LABORATORY
SYLLABUS


? To make the student to acquire practical skills in the determination of water quality
parameters through volumetric and instrumental analysis.

? ???? ??? ???? ?? ???? ? ? ?To acquaint the students with the determination of molecular weight of a polymer by
viscometery.

LIST OF EXPERIMENTS:
1. Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. Determination of total, temporary & permanent hardness of water by EDTA method.
3. Determination of DO content of water sample by Winkler?s method.
4. Determination of chloride content of water sample by Argentometric method.
5. Estimation of copper content of the given solution by Iodometry.
6. Determination of strength of given hydrochloric acid using pH meter.
7. Determination of strength of acids in a mixture of acids using conductivity meter.
8. Estimation of iron content of the given solution using potentiometer.
9. Estimation of iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. Estimation of sodium and potassium present in water using flame photometer.
11. Determination of molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. Pseudo first order kinetics ? ester hydrolysis.
13. Corrosion experiment ? weight loss method.
14. Determination of CMC.
15. Phase change in a solid.
16. Conductometric titration of strong acid vs strong base.




? The students will be outfitted with hands-on knowledge in the quantitative chemical
analysis of water quality related parameters.
COURSE OBJECTIVES
COURSE OUTCOMES
6


INDEX [ SEMESTER ? I ]


S.No.



Date


Experiment

Date of
submission



Mark


Signature

1.

Estimation of HCl using Na 2CO 3 as
primary standard and Determination of
alkalinity in water sample.



2.


Determination of total, temporary &
permanent hardness of water by EDTA
method.



3.


Determination of chloride content of water
sample by argentometric method.



4.


Determination of strength of given
hydrochloric acid using pH meter.



5.


Determination of strength of acids in a
mixture of acids using conductivity meter.



6.


Estimation of iron content of the given
solution using potentiometer.



7.





Conductometric titration of strong acid Vs
strong base.



8.



Estimation of copper content of the given
solution by Iodometry


9.
Estimation of sodium and potassium
present in water using flame photometer




7




CONTENTS


S.No.


NAME OF EXPERIMENT

PAGE
No.
SEMESTER - I
1.
Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in
water sample.
09
2. Determination of total, temporary & permanent hardness of water by EDTA method. 15
3. Determination of chloride content of water sample by Argentometric method. 21
4. Determination of strength of given hydrochloric acid using pH meter. 25
5. Determination of strength of acids in a mixture of acids using conductivity meter. 29
6. Estimation of iron content of the given solution using potentiometer. 33
7. Conductometric titration of strong acid Vs strong base.

39


42

8


Estimation of copper content of the given solution by Iodometry 43
9 Estimation of sodium and potassium present in water using flame photometer 47






8



SHORT PROCEDURE:

CONTENTS
TITRATION
Estimation of alkalinity in water sample
(Std HCl Vs water sample)

Burette solution

Std. HCl


Pipette solution

Water sample


Indicator


(i) Phenolphthalein
(ii) Methyl orange


End point

(i) Disappearance of pink colour
(ii) Appearance of reddish orange colour






Relationship
between P &M
Nature of alkalinity
Amount of individual
alkalinities
OH
-
HCO 3
-


CO 3
2-

P = M

only OH
-

P or M

?
0.0

0.0


2P = M

only CO 3
2-


2P or M


0.0


0.0


?

P =0, M?0

only HCO 3
-



M



0.0



?

0.0


2P > M


OH
-
&CO 3
2-


OH
-
= 2P-M
CO 3
2-
= 2(M-P)


?

0.0

?

P < ? M




HCO 3
-
&CO 3
2-


HCO 3
-
= M-2P
CO 3
2-
= 2P

0.0 ? ?




9





Expt. No. 1 DETERMINATION OF ALKALINITY IN WATER
AIM
To determine the type and amounts of alkalinity in the given water sample. A standard solution of Na 2CO 3
of strength ____N is given.

PRINCIPLE
Alkalinity in water is due to the presence of soluble hydroxides, bicarbonates and carbonates.
Determination of various types and amounts of alkalinity is easily carried out by titration with standard HCl
employing the indicators phenolphthalein and methyl orange independently or in succession.

The following reactions occur when different types of alkalinity are neutralized with acid.

OH
?
+ H
+
? H 2O completed at pH 8.2-9.0 ----- (1)

CO 3
2 ?
+ H
+
? HCO 3
?
----- (2)

HCO 3
?
+ H
+
? (H 2CO 3) ? H 2O + CO 2, completed at pH 4.2-5.5 ----- (3)

Neutralisation (1) & (2) will be notified by phenolphthalein end-point while all the three will be

accounted by
methyl orange end-point. Bicarbonate in eqn. (3) may be due to the existence of soluble free bicarbonate salts and
bicarbonates resulting from half neutralization of soluble carbonates (eqn. (2))

Various steps to be followed

a) A known volume of water sample is titrated against std. HCl using first phenolphthalein indicator till
end-point (P) and the titration is continued without break using methyl orange indicator till the end-
point (M).



10


Titration

Estimation of Alkalinity in water sample

Standard HCl Vs Water sample Indicator: 1. Phenolphthalein
2. Methyl Orange


S.No.
Volume
of water
sample (ml)
Burette Reading
Concordant value

Initial Phenolphthalein End
Point (P)
Methyl Orange End
Point (M)

1

2






CALCULATION

Hydroxide ion alkalinity
Volume of HCl (2P-M) = ???????ml

Strength of HCl = ???????? N

Volume of water sample = ???????...ml

Strength of water sample = Volume of HCl (2P-M) x Strength of HCl
Volume of water sample

=

? Hydroxide ion alkalinity in terms of
CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ??????.mg/l







FirstRanker.com - FirstRanker's Choice



?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





3


PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)
1. Fundamentals
To provide students with a solid foundation in Mathematics, Science and fundamentals of engineering,
enabling them to apply, to find solutions for engineering problems and use this knowledge to acquire higher
education
2. Core Competence
To train the students in chemistry practicals so that they apply their knowledge and training to compare,
and to analyze various engineering industrial problems to find solutions
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice this enables
them to find solutions for the real time problems in industry, and to design products
4. Professionalism
To inculcate professional and effective communication skills, leadership qualities and team spirit in the
students to make them multi-faceted personalities and develop their ability to relate engineering issues to
broader social context
5. Lifelong Learning/Ethics
To demonstrate and practice ethical and professional responsibilities in the industry and society in the
large, through commitment and lifelong learning needed for successful professional career






4


PROGRAMME OUTCOMES (POs)
To demonstrate and apply knowledge of Mathematics, Science and engineering fundamentals in the following
experiments.
1 .To estimate HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. To determine total, temporary & permanent hardness of water by EDTA method.
3. To determine DO content of water sample by Winkler?s method.
4. To determine chloride content of water sample by Argentometric method.
5. To estimate copper content of the given solution by Iodometry.
6. To determine strength of given hydrochloric acid using pH meter.
7. To determine strength of acids in a mixture of acids using conductivity meter.
8. To determine iron content of the given solution using potentiometer.
9. To estimate iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. To estimate sodium and potassium present in water using flame photometer.
11. To determine molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. To determine Pseudo first order kinetics ? ester hydrolysis.
13. To determine Corrosion experiment ? weight loss method.
14. To estimate CMC.
15. To estimate Phase change in a solid.
16. To determine strength of strong acid vs strong base using conductivity meter.











5

BS8161 - CHEMISTRY LABORATORY
SYLLABUS


? To make the student to acquire practical skills in the determination of water quality
parameters through volumetric and instrumental analysis.

? ???? ??? ???? ?? ???? ? ? ?To acquaint the students with the determination of molecular weight of a polymer by
viscometery.

LIST OF EXPERIMENTS:
1. Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. Determination of total, temporary & permanent hardness of water by EDTA method.
3. Determination of DO content of water sample by Winkler?s method.
4. Determination of chloride content of water sample by Argentometric method.
5. Estimation of copper content of the given solution by Iodometry.
6. Determination of strength of given hydrochloric acid using pH meter.
7. Determination of strength of acids in a mixture of acids using conductivity meter.
8. Estimation of iron content of the given solution using potentiometer.
9. Estimation of iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. Estimation of sodium and potassium present in water using flame photometer.
11. Determination of molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. Pseudo first order kinetics ? ester hydrolysis.
13. Corrosion experiment ? weight loss method.
14. Determination of CMC.
15. Phase change in a solid.
16. Conductometric titration of strong acid vs strong base.




? The students will be outfitted with hands-on knowledge in the quantitative chemical
analysis of water quality related parameters.
COURSE OBJECTIVES
COURSE OUTCOMES
6


INDEX [ SEMESTER ? I ]


S.No.



Date


Experiment

Date of
submission



Mark


Signature

1.

Estimation of HCl using Na 2CO 3 as
primary standard and Determination of
alkalinity in water sample.



2.


Determination of total, temporary &
permanent hardness of water by EDTA
method.



3.


Determination of chloride content of water
sample by argentometric method.



4.


Determination of strength of given
hydrochloric acid using pH meter.



5.


Determination of strength of acids in a
mixture of acids using conductivity meter.



6.


Estimation of iron content of the given
solution using potentiometer.



7.





Conductometric titration of strong acid Vs
strong base.



8.



Estimation of copper content of the given
solution by Iodometry


9.
Estimation of sodium and potassium
present in water using flame photometer




7




CONTENTS


S.No.


NAME OF EXPERIMENT

PAGE
No.
SEMESTER - I
1.
Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in
water sample.
09
2. Determination of total, temporary & permanent hardness of water by EDTA method. 15
3. Determination of chloride content of water sample by Argentometric method. 21
4. Determination of strength of given hydrochloric acid using pH meter. 25
5. Determination of strength of acids in a mixture of acids using conductivity meter. 29
6. Estimation of iron content of the given solution using potentiometer. 33
7. Conductometric titration of strong acid Vs strong base.

39


42

8


Estimation of copper content of the given solution by Iodometry 43
9 Estimation of sodium and potassium present in water using flame photometer 47






8



SHORT PROCEDURE:

CONTENTS
TITRATION
Estimation of alkalinity in water sample
(Std HCl Vs water sample)

Burette solution

Std. HCl


Pipette solution

Water sample


Indicator


(i) Phenolphthalein
(ii) Methyl orange


End point

(i) Disappearance of pink colour
(ii) Appearance of reddish orange colour






Relationship
between P &M
Nature of alkalinity
Amount of individual
alkalinities
OH
-
HCO 3
-


CO 3
2-

P = M

only OH
-

P or M

?
0.0

0.0


2P = M

only CO 3
2-


2P or M


0.0


0.0


?

P =0, M?0

only HCO 3
-



M



0.0



?

0.0


2P > M


OH
-
&CO 3
2-


OH
-
= 2P-M
CO 3
2-
= 2(M-P)


?

0.0

?

P < ? M




HCO 3
-
&CO 3
2-


HCO 3
-
= M-2P
CO 3
2-
= 2P

0.0 ? ?




9





Expt. No. 1 DETERMINATION OF ALKALINITY IN WATER
AIM
To determine the type and amounts of alkalinity in the given water sample. A standard solution of Na 2CO 3
of strength ____N is given.

PRINCIPLE
Alkalinity in water is due to the presence of soluble hydroxides, bicarbonates and carbonates.
Determination of various types and amounts of alkalinity is easily carried out by titration with standard HCl
employing the indicators phenolphthalein and methyl orange independently or in succession.

The following reactions occur when different types of alkalinity are neutralized with acid.

OH
?
+ H
+
? H 2O completed at pH 8.2-9.0 ----- (1)

CO 3
2 ?
+ H
+
? HCO 3
?
----- (2)

HCO 3
?
+ H
+
? (H 2CO 3) ? H 2O + CO 2, completed at pH 4.2-5.5 ----- (3)

Neutralisation (1) & (2) will be notified by phenolphthalein end-point while all the three will be

accounted by
methyl orange end-point. Bicarbonate in eqn. (3) may be due to the existence of soluble free bicarbonate salts and
bicarbonates resulting from half neutralization of soluble carbonates (eqn. (2))

Various steps to be followed

a) A known volume of water sample is titrated against std. HCl using first phenolphthalein indicator till
end-point (P) and the titration is continued without break using methyl orange indicator till the end-
point (M).



10


Titration

Estimation of Alkalinity in water sample

Standard HCl Vs Water sample Indicator: 1. Phenolphthalein
2. Methyl Orange


S.No.
Volume
of water
sample (ml)
Burette Reading
Concordant value

Initial Phenolphthalein End
Point (P)
Methyl Orange End
Point (M)

1

2






CALCULATION

Hydroxide ion alkalinity
Volume of HCl (2P-M) = ???????ml

Strength of HCl = ???????? N

Volume of water sample = ???????...ml

Strength of water sample = Volume of HCl (2P-M) x Strength of HCl
Volume of water sample

=

? Hydroxide ion alkalinity in terms of
CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ??????.mg/l







11




b) From the magnitudes of the P & M, the nature of alkalinity can be arrived as follows:

(i) P = M => Presence of only OH
-

(ii) 2P = M => Presence of only CO 3
2-

(iii) P =0, M=0 => Presence of only HCO 3
-
(iv) 2P > M => Presence of OH
-
& CO 3
2-
(v) 2P < M => Presence of HCO 3
-
& CO 3
2-

(Mixture of OH
-
& HCO3
-
is not listed since they do not exist together and are considered equivalent to CO 3
2-
).

PROCEDURE
TITRATION
ESTIMATION OF ALKALINITY IN WATER SAMPLE

Exactly 20 ml of water sample is pipetted out into a clean conical flask. Few drops of phenolphthalein
indicator are added and titrated against a standardized HCl taken in the burette. The end point is the
disappearance of pink colour, which is noted as P. Few drops of methyl orange indicator is added to the same
solution. The solution turns to yellow. The titration is continued further by adding same HCl without break till the
end point is reached. The end point is the colour change from yellow to reddish orange.

The experiment is repeated to get concordant values. From the magnitudes of P & M values, the type of
alkalinity present in the water sample is inferred and the individual amounts are calculated and reported.










FirstRanker.com - FirstRanker's Choice



?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





3


PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)
1. Fundamentals
To provide students with a solid foundation in Mathematics, Science and fundamentals of engineering,
enabling them to apply, to find solutions for engineering problems and use this knowledge to acquire higher
education
2. Core Competence
To train the students in chemistry practicals so that they apply their knowledge and training to compare,
and to analyze various engineering industrial problems to find solutions
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice this enables
them to find solutions for the real time problems in industry, and to design products
4. Professionalism
To inculcate professional and effective communication skills, leadership qualities and team spirit in the
students to make them multi-faceted personalities and develop their ability to relate engineering issues to
broader social context
5. Lifelong Learning/Ethics
To demonstrate and practice ethical and professional responsibilities in the industry and society in the
large, through commitment and lifelong learning needed for successful professional career






4


PROGRAMME OUTCOMES (POs)
To demonstrate and apply knowledge of Mathematics, Science and engineering fundamentals in the following
experiments.
1 .To estimate HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. To determine total, temporary & permanent hardness of water by EDTA method.
3. To determine DO content of water sample by Winkler?s method.
4. To determine chloride content of water sample by Argentometric method.
5. To estimate copper content of the given solution by Iodometry.
6. To determine strength of given hydrochloric acid using pH meter.
7. To determine strength of acids in a mixture of acids using conductivity meter.
8. To determine iron content of the given solution using potentiometer.
9. To estimate iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. To estimate sodium and potassium present in water using flame photometer.
11. To determine molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. To determine Pseudo first order kinetics ? ester hydrolysis.
13. To determine Corrosion experiment ? weight loss method.
14. To estimate CMC.
15. To estimate Phase change in a solid.
16. To determine strength of strong acid vs strong base using conductivity meter.











5

BS8161 - CHEMISTRY LABORATORY
SYLLABUS


? To make the student to acquire practical skills in the determination of water quality
parameters through volumetric and instrumental analysis.

? ???? ??? ???? ?? ???? ? ? ?To acquaint the students with the determination of molecular weight of a polymer by
viscometery.

LIST OF EXPERIMENTS:
1. Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. Determination of total, temporary & permanent hardness of water by EDTA method.
3. Determination of DO content of water sample by Winkler?s method.
4. Determination of chloride content of water sample by Argentometric method.
5. Estimation of copper content of the given solution by Iodometry.
6. Determination of strength of given hydrochloric acid using pH meter.
7. Determination of strength of acids in a mixture of acids using conductivity meter.
8. Estimation of iron content of the given solution using potentiometer.
9. Estimation of iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. Estimation of sodium and potassium present in water using flame photometer.
11. Determination of molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. Pseudo first order kinetics ? ester hydrolysis.
13. Corrosion experiment ? weight loss method.
14. Determination of CMC.
15. Phase change in a solid.
16. Conductometric titration of strong acid vs strong base.




? The students will be outfitted with hands-on knowledge in the quantitative chemical
analysis of water quality related parameters.
COURSE OBJECTIVES
COURSE OUTCOMES
6


INDEX [ SEMESTER ? I ]


S.No.



Date


Experiment

Date of
submission



Mark


Signature

1.

Estimation of HCl using Na 2CO 3 as
primary standard and Determination of
alkalinity in water sample.



2.


Determination of total, temporary &
permanent hardness of water by EDTA
method.



3.


Determination of chloride content of water
sample by argentometric method.



4.


Determination of strength of given
hydrochloric acid using pH meter.



5.


Determination of strength of acids in a
mixture of acids using conductivity meter.



6.


Estimation of iron content of the given
solution using potentiometer.



7.





Conductometric titration of strong acid Vs
strong base.



8.



Estimation of copper content of the given
solution by Iodometry


9.
Estimation of sodium and potassium
present in water using flame photometer




7




CONTENTS


S.No.


NAME OF EXPERIMENT

PAGE
No.
SEMESTER - I
1.
Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in
water sample.
09
2. Determination of total, temporary & permanent hardness of water by EDTA method. 15
3. Determination of chloride content of water sample by Argentometric method. 21
4. Determination of strength of given hydrochloric acid using pH meter. 25
5. Determination of strength of acids in a mixture of acids using conductivity meter. 29
6. Estimation of iron content of the given solution using potentiometer. 33
7. Conductometric titration of strong acid Vs strong base.

39


42

8


Estimation of copper content of the given solution by Iodometry 43
9 Estimation of sodium and potassium present in water using flame photometer 47






8



SHORT PROCEDURE:

CONTENTS
TITRATION
Estimation of alkalinity in water sample
(Std HCl Vs water sample)

Burette solution

Std. HCl


Pipette solution

Water sample


Indicator


(i) Phenolphthalein
(ii) Methyl orange


End point

(i) Disappearance of pink colour
(ii) Appearance of reddish orange colour






Relationship
between P &M
Nature of alkalinity
Amount of individual
alkalinities
OH
-
HCO 3
-


CO 3
2-

P = M

only OH
-

P or M

?
0.0

0.0


2P = M

only CO 3
2-


2P or M


0.0


0.0


?

P =0, M?0

only HCO 3
-



M



0.0



?

0.0


2P > M


OH
-
&CO 3
2-


OH
-
= 2P-M
CO 3
2-
= 2(M-P)


?

0.0

?

P < ? M




HCO 3
-
&CO 3
2-


HCO 3
-
= M-2P
CO 3
2-
= 2P

0.0 ? ?




9





Expt. No. 1 DETERMINATION OF ALKALINITY IN WATER
AIM
To determine the type and amounts of alkalinity in the given water sample. A standard solution of Na 2CO 3
of strength ____N is given.

PRINCIPLE
Alkalinity in water is due to the presence of soluble hydroxides, bicarbonates and carbonates.
Determination of various types and amounts of alkalinity is easily carried out by titration with standard HCl
employing the indicators phenolphthalein and methyl orange independently or in succession.

The following reactions occur when different types of alkalinity are neutralized with acid.

OH
?
+ H
+
? H 2O completed at pH 8.2-9.0 ----- (1)

CO 3
2 ?
+ H
+
? HCO 3
?
----- (2)

HCO 3
?
+ H
+
? (H 2CO 3) ? H 2O + CO 2, completed at pH 4.2-5.5 ----- (3)

Neutralisation (1) & (2) will be notified by phenolphthalein end-point while all the three will be

accounted by
methyl orange end-point. Bicarbonate in eqn. (3) may be due to the existence of soluble free bicarbonate salts and
bicarbonates resulting from half neutralization of soluble carbonates (eqn. (2))

Various steps to be followed

a) A known volume of water sample is titrated against std. HCl using first phenolphthalein indicator till
end-point (P) and the titration is continued without break using methyl orange indicator till the end-
point (M).



10


Titration

Estimation of Alkalinity in water sample

Standard HCl Vs Water sample Indicator: 1. Phenolphthalein
2. Methyl Orange


S.No.
Volume
of water
sample (ml)
Burette Reading
Concordant value

Initial Phenolphthalein End
Point (P)
Methyl Orange End
Point (M)

1

2






CALCULATION

Hydroxide ion alkalinity
Volume of HCl (2P-M) = ???????ml

Strength of HCl = ???????? N

Volume of water sample = ???????...ml

Strength of water sample = Volume of HCl (2P-M) x Strength of HCl
Volume of water sample

=

? Hydroxide ion alkalinity in terms of
CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ??????.mg/l







11




b) From the magnitudes of the P & M, the nature of alkalinity can be arrived as follows:

(i) P = M => Presence of only OH
-

(ii) 2P = M => Presence of only CO 3
2-

(iii) P =0, M=0 => Presence of only HCO 3
-
(iv) 2P > M => Presence of OH
-
& CO 3
2-
(v) 2P < M => Presence of HCO 3
-
& CO 3
2-

(Mixture of OH
-
& HCO3
-
is not listed since they do not exist together and are considered equivalent to CO 3
2-
).

PROCEDURE
TITRATION
ESTIMATION OF ALKALINITY IN WATER SAMPLE

Exactly 20 ml of water sample is pipetted out into a clean conical flask. Few drops of phenolphthalein
indicator are added and titrated against a standardized HCl taken in the burette. The end point is the
disappearance of pink colour, which is noted as P. Few drops of methyl orange indicator is added to the same
solution. The solution turns to yellow. The titration is continued further by adding same HCl without break till the
end point is reached. The end point is the colour change from yellow to reddish orange.

The experiment is repeated to get concordant values. From the magnitudes of P & M values, the type of
alkalinity present in the water sample is inferred and the individual amounts are calculated and reported.










12


Carbonate ion alkalinity

Volume of HCl 2 (M ? P) = ??? ????????ml

Strength of HCl = ??.?????..???...N

Volume of water sample =........................................ml

Strength of water sample = Volume of HCl 2 (M ? P) x Strength of HCl
Volume of water sample

= ???????????.. N




? Carbonate ion alkalinity
in terms of CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ???????????mg/l

















FirstRanker.com - FirstRanker's Choice



?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





3


PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)
1. Fundamentals
To provide students with a solid foundation in Mathematics, Science and fundamentals of engineering,
enabling them to apply, to find solutions for engineering problems and use this knowledge to acquire higher
education
2. Core Competence
To train the students in chemistry practicals so that they apply their knowledge and training to compare,
and to analyze various engineering industrial problems to find solutions
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice this enables
them to find solutions for the real time problems in industry, and to design products
4. Professionalism
To inculcate professional and effective communication skills, leadership qualities and team spirit in the
students to make them multi-faceted personalities and develop their ability to relate engineering issues to
broader social context
5. Lifelong Learning/Ethics
To demonstrate and practice ethical and professional responsibilities in the industry and society in the
large, through commitment and lifelong learning needed for successful professional career






4


PROGRAMME OUTCOMES (POs)
To demonstrate and apply knowledge of Mathematics, Science and engineering fundamentals in the following
experiments.
1 .To estimate HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. To determine total, temporary & permanent hardness of water by EDTA method.
3. To determine DO content of water sample by Winkler?s method.
4. To determine chloride content of water sample by Argentometric method.
5. To estimate copper content of the given solution by Iodometry.
6. To determine strength of given hydrochloric acid using pH meter.
7. To determine strength of acids in a mixture of acids using conductivity meter.
8. To determine iron content of the given solution using potentiometer.
9. To estimate iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. To estimate sodium and potassium present in water using flame photometer.
11. To determine molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. To determine Pseudo first order kinetics ? ester hydrolysis.
13. To determine Corrosion experiment ? weight loss method.
14. To estimate CMC.
15. To estimate Phase change in a solid.
16. To determine strength of strong acid vs strong base using conductivity meter.











5

BS8161 - CHEMISTRY LABORATORY
SYLLABUS


? To make the student to acquire practical skills in the determination of water quality
parameters through volumetric and instrumental analysis.

? ???? ??? ???? ?? ???? ? ? ?To acquaint the students with the determination of molecular weight of a polymer by
viscometery.

LIST OF EXPERIMENTS:
1. Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. Determination of total, temporary & permanent hardness of water by EDTA method.
3. Determination of DO content of water sample by Winkler?s method.
4. Determination of chloride content of water sample by Argentometric method.
5. Estimation of copper content of the given solution by Iodometry.
6. Determination of strength of given hydrochloric acid using pH meter.
7. Determination of strength of acids in a mixture of acids using conductivity meter.
8. Estimation of iron content of the given solution using potentiometer.
9. Estimation of iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. Estimation of sodium and potassium present in water using flame photometer.
11. Determination of molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. Pseudo first order kinetics ? ester hydrolysis.
13. Corrosion experiment ? weight loss method.
14. Determination of CMC.
15. Phase change in a solid.
16. Conductometric titration of strong acid vs strong base.




? The students will be outfitted with hands-on knowledge in the quantitative chemical
analysis of water quality related parameters.
COURSE OBJECTIVES
COURSE OUTCOMES
6


INDEX [ SEMESTER ? I ]


S.No.



Date


Experiment

Date of
submission



Mark


Signature

1.

Estimation of HCl using Na 2CO 3 as
primary standard and Determination of
alkalinity in water sample.



2.


Determination of total, temporary &
permanent hardness of water by EDTA
method.



3.


Determination of chloride content of water
sample by argentometric method.



4.


Determination of strength of given
hydrochloric acid using pH meter.



5.


Determination of strength of acids in a
mixture of acids using conductivity meter.



6.


Estimation of iron content of the given
solution using potentiometer.



7.





Conductometric titration of strong acid Vs
strong base.



8.



Estimation of copper content of the given
solution by Iodometry


9.
Estimation of sodium and potassium
present in water using flame photometer




7




CONTENTS


S.No.


NAME OF EXPERIMENT

PAGE
No.
SEMESTER - I
1.
Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in
water sample.
09
2. Determination of total, temporary & permanent hardness of water by EDTA method. 15
3. Determination of chloride content of water sample by Argentometric method. 21
4. Determination of strength of given hydrochloric acid using pH meter. 25
5. Determination of strength of acids in a mixture of acids using conductivity meter. 29
6. Estimation of iron content of the given solution using potentiometer. 33
7. Conductometric titration of strong acid Vs strong base.

39


42

8


Estimation of copper content of the given solution by Iodometry 43
9 Estimation of sodium and potassium present in water using flame photometer 47






8



SHORT PROCEDURE:

CONTENTS
TITRATION
Estimation of alkalinity in water sample
(Std HCl Vs water sample)

Burette solution

Std. HCl


Pipette solution

Water sample


Indicator


(i) Phenolphthalein
(ii) Methyl orange


End point

(i) Disappearance of pink colour
(ii) Appearance of reddish orange colour






Relationship
between P &M
Nature of alkalinity
Amount of individual
alkalinities
OH
-
HCO 3
-


CO 3
2-

P = M

only OH
-

P or M

?
0.0

0.0


2P = M

only CO 3
2-


2P or M


0.0


0.0


?

P =0, M?0

only HCO 3
-



M



0.0



?

0.0


2P > M


OH
-
&CO 3
2-


OH
-
= 2P-M
CO 3
2-
= 2(M-P)


?

0.0

?

P < ? M




HCO 3
-
&CO 3
2-


HCO 3
-
= M-2P
CO 3
2-
= 2P

0.0 ? ?




9





Expt. No. 1 DETERMINATION OF ALKALINITY IN WATER
AIM
To determine the type and amounts of alkalinity in the given water sample. A standard solution of Na 2CO 3
of strength ____N is given.

PRINCIPLE
Alkalinity in water is due to the presence of soluble hydroxides, bicarbonates and carbonates.
Determination of various types and amounts of alkalinity is easily carried out by titration with standard HCl
employing the indicators phenolphthalein and methyl orange independently or in succession.

The following reactions occur when different types of alkalinity are neutralized with acid.

OH
?
+ H
+
? H 2O completed at pH 8.2-9.0 ----- (1)

CO 3
2 ?
+ H
+
? HCO 3
?
----- (2)

HCO 3
?
+ H
+
? (H 2CO 3) ? H 2O + CO 2, completed at pH 4.2-5.5 ----- (3)

Neutralisation (1) & (2) will be notified by phenolphthalein end-point while all the three will be

accounted by
methyl orange end-point. Bicarbonate in eqn. (3) may be due to the existence of soluble free bicarbonate salts and
bicarbonates resulting from half neutralization of soluble carbonates (eqn. (2))

Various steps to be followed

a) A known volume of water sample is titrated against std. HCl using first phenolphthalein indicator till
end-point (P) and the titration is continued without break using methyl orange indicator till the end-
point (M).



10


Titration

Estimation of Alkalinity in water sample

Standard HCl Vs Water sample Indicator: 1. Phenolphthalein
2. Methyl Orange


S.No.
Volume
of water
sample (ml)
Burette Reading
Concordant value

Initial Phenolphthalein End
Point (P)
Methyl Orange End
Point (M)

1

2






CALCULATION

Hydroxide ion alkalinity
Volume of HCl (2P-M) = ???????ml

Strength of HCl = ???????? N

Volume of water sample = ???????...ml

Strength of water sample = Volume of HCl (2P-M) x Strength of HCl
Volume of water sample

=

? Hydroxide ion alkalinity in terms of
CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ??????.mg/l







11




b) From the magnitudes of the P & M, the nature of alkalinity can be arrived as follows:

(i) P = M => Presence of only OH
-

(ii) 2P = M => Presence of only CO 3
2-

(iii) P =0, M=0 => Presence of only HCO 3
-
(iv) 2P > M => Presence of OH
-
& CO 3
2-
(v) 2P < M => Presence of HCO 3
-
& CO 3
2-

(Mixture of OH
-
& HCO3
-
is not listed since they do not exist together and are considered equivalent to CO 3
2-
).

PROCEDURE
TITRATION
ESTIMATION OF ALKALINITY IN WATER SAMPLE

Exactly 20 ml of water sample is pipetted out into a clean conical flask. Few drops of phenolphthalein
indicator are added and titrated against a standardized HCl taken in the burette. The end point is the
disappearance of pink colour, which is noted as P. Few drops of methyl orange indicator is added to the same
solution. The solution turns to yellow. The titration is continued further by adding same HCl without break till the
end point is reached. The end point is the colour change from yellow to reddish orange.

The experiment is repeated to get concordant values. From the magnitudes of P & M values, the type of
alkalinity present in the water sample is inferred and the individual amounts are calculated and reported.










12


Carbonate ion alkalinity

Volume of HCl 2 (M ? P) = ??? ????????ml

Strength of HCl = ??.?????..???...N

Volume of water sample =........................................ml

Strength of water sample = Volume of HCl 2 (M ? P) x Strength of HCl
Volume of water sample

= ???????????.. N




? Carbonate ion alkalinity
in terms of CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ???????????mg/l

















13





RESULT

1) The type of alkalinity present in the water sample = -------------------------ions.

2) The individual amounts of alkalinity present in the water sample:
Hydroxide ion alkalinity

= ----------------- ppm
Carbonate ion alkalinity = ------------------ ppm
Bicarbonate ion alkalinity = ----------------- ppm





VIVA-VOCE


1. What is meant by alkalinity?
2. What are the ions responsible for alkalinity?
3. Why OH
-
and HCO 3
?
ions cannot exist together in water?
4. What are the ions responsible for alkalinity when 2P > M?
5. What is the pH range for both in acidic and basic solutions?
6. What is the colour of phenolphthalein in an acid and in an alkaline solution?
7. What is the purpose of using two indicators in same titration?
8. What are the possible combinations of ions for alkalinity?
9. How is the amount of alkalinity expressed?
10. What are the types of indicator used in this experiment?







FirstRanker.com - FirstRanker's Choice



?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





3


PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)
1. Fundamentals
To provide students with a solid foundation in Mathematics, Science and fundamentals of engineering,
enabling them to apply, to find solutions for engineering problems and use this knowledge to acquire higher
education
2. Core Competence
To train the students in chemistry practicals so that they apply their knowledge and training to compare,
and to analyze various engineering industrial problems to find solutions
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice this enables
them to find solutions for the real time problems in industry, and to design products
4. Professionalism
To inculcate professional and effective communication skills, leadership qualities and team spirit in the
students to make them multi-faceted personalities and develop their ability to relate engineering issues to
broader social context
5. Lifelong Learning/Ethics
To demonstrate and practice ethical and professional responsibilities in the industry and society in the
large, through commitment and lifelong learning needed for successful professional career






4


PROGRAMME OUTCOMES (POs)
To demonstrate and apply knowledge of Mathematics, Science and engineering fundamentals in the following
experiments.
1 .To estimate HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. To determine total, temporary & permanent hardness of water by EDTA method.
3. To determine DO content of water sample by Winkler?s method.
4. To determine chloride content of water sample by Argentometric method.
5. To estimate copper content of the given solution by Iodometry.
6. To determine strength of given hydrochloric acid using pH meter.
7. To determine strength of acids in a mixture of acids using conductivity meter.
8. To determine iron content of the given solution using potentiometer.
9. To estimate iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. To estimate sodium and potassium present in water using flame photometer.
11. To determine molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. To determine Pseudo first order kinetics ? ester hydrolysis.
13. To determine Corrosion experiment ? weight loss method.
14. To estimate CMC.
15. To estimate Phase change in a solid.
16. To determine strength of strong acid vs strong base using conductivity meter.











5

BS8161 - CHEMISTRY LABORATORY
SYLLABUS


? To make the student to acquire practical skills in the determination of water quality
parameters through volumetric and instrumental analysis.

? ???? ??? ???? ?? ???? ? ? ?To acquaint the students with the determination of molecular weight of a polymer by
viscometery.

LIST OF EXPERIMENTS:
1. Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. Determination of total, temporary & permanent hardness of water by EDTA method.
3. Determination of DO content of water sample by Winkler?s method.
4. Determination of chloride content of water sample by Argentometric method.
5. Estimation of copper content of the given solution by Iodometry.
6. Determination of strength of given hydrochloric acid using pH meter.
7. Determination of strength of acids in a mixture of acids using conductivity meter.
8. Estimation of iron content of the given solution using potentiometer.
9. Estimation of iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. Estimation of sodium and potassium present in water using flame photometer.
11. Determination of molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. Pseudo first order kinetics ? ester hydrolysis.
13. Corrosion experiment ? weight loss method.
14. Determination of CMC.
15. Phase change in a solid.
16. Conductometric titration of strong acid vs strong base.




? The students will be outfitted with hands-on knowledge in the quantitative chemical
analysis of water quality related parameters.
COURSE OBJECTIVES
COURSE OUTCOMES
6


INDEX [ SEMESTER ? I ]


S.No.



Date


Experiment

Date of
submission



Mark


Signature

1.

Estimation of HCl using Na 2CO 3 as
primary standard and Determination of
alkalinity in water sample.



2.


Determination of total, temporary &
permanent hardness of water by EDTA
method.



3.


Determination of chloride content of water
sample by argentometric method.



4.


Determination of strength of given
hydrochloric acid using pH meter.



5.


Determination of strength of acids in a
mixture of acids using conductivity meter.



6.


Estimation of iron content of the given
solution using potentiometer.



7.





Conductometric titration of strong acid Vs
strong base.



8.



Estimation of copper content of the given
solution by Iodometry


9.
Estimation of sodium and potassium
present in water using flame photometer




7




CONTENTS


S.No.


NAME OF EXPERIMENT

PAGE
No.
SEMESTER - I
1.
Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in
water sample.
09
2. Determination of total, temporary & permanent hardness of water by EDTA method. 15
3. Determination of chloride content of water sample by Argentometric method. 21
4. Determination of strength of given hydrochloric acid using pH meter. 25
5. Determination of strength of acids in a mixture of acids using conductivity meter. 29
6. Estimation of iron content of the given solution using potentiometer. 33
7. Conductometric titration of strong acid Vs strong base.

39


42

8


Estimation of copper content of the given solution by Iodometry 43
9 Estimation of sodium and potassium present in water using flame photometer 47






8



SHORT PROCEDURE:

CONTENTS
TITRATION
Estimation of alkalinity in water sample
(Std HCl Vs water sample)

Burette solution

Std. HCl


Pipette solution

Water sample


Indicator


(i) Phenolphthalein
(ii) Methyl orange


End point

(i) Disappearance of pink colour
(ii) Appearance of reddish orange colour






Relationship
between P &M
Nature of alkalinity
Amount of individual
alkalinities
OH
-
HCO 3
-


CO 3
2-

P = M

only OH
-

P or M

?
0.0

0.0


2P = M

only CO 3
2-


2P or M


0.0


0.0


?

P =0, M?0

only HCO 3
-



M



0.0



?

0.0


2P > M


OH
-
&CO 3
2-


OH
-
= 2P-M
CO 3
2-
= 2(M-P)


?

0.0

?

P < ? M




HCO 3
-
&CO 3
2-


HCO 3
-
= M-2P
CO 3
2-
= 2P

0.0 ? ?




9





Expt. No. 1 DETERMINATION OF ALKALINITY IN WATER
AIM
To determine the type and amounts of alkalinity in the given water sample. A standard solution of Na 2CO 3
of strength ____N is given.

PRINCIPLE
Alkalinity in water is due to the presence of soluble hydroxides, bicarbonates and carbonates.
Determination of various types and amounts of alkalinity is easily carried out by titration with standard HCl
employing the indicators phenolphthalein and methyl orange independently or in succession.

The following reactions occur when different types of alkalinity are neutralized with acid.

OH
?
+ H
+
? H 2O completed at pH 8.2-9.0 ----- (1)

CO 3
2 ?
+ H
+
? HCO 3
?
----- (2)

HCO 3
?
+ H
+
? (H 2CO 3) ? H 2O + CO 2, completed at pH 4.2-5.5 ----- (3)

Neutralisation (1) & (2) will be notified by phenolphthalein end-point while all the three will be

accounted by
methyl orange end-point. Bicarbonate in eqn. (3) may be due to the existence of soluble free bicarbonate salts and
bicarbonates resulting from half neutralization of soluble carbonates (eqn. (2))

Various steps to be followed

a) A known volume of water sample is titrated against std. HCl using first phenolphthalein indicator till
end-point (P) and the titration is continued without break using methyl orange indicator till the end-
point (M).



10


Titration

Estimation of Alkalinity in water sample

Standard HCl Vs Water sample Indicator: 1. Phenolphthalein
2. Methyl Orange


S.No.
Volume
of water
sample (ml)
Burette Reading
Concordant value

Initial Phenolphthalein End
Point (P)
Methyl Orange End
Point (M)

1

2






CALCULATION

Hydroxide ion alkalinity
Volume of HCl (2P-M) = ???????ml

Strength of HCl = ???????? N

Volume of water sample = ???????...ml

Strength of water sample = Volume of HCl (2P-M) x Strength of HCl
Volume of water sample

=

? Hydroxide ion alkalinity in terms of
CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ??????.mg/l







11




b) From the magnitudes of the P & M, the nature of alkalinity can be arrived as follows:

(i) P = M => Presence of only OH
-

(ii) 2P = M => Presence of only CO 3
2-

(iii) P =0, M=0 => Presence of only HCO 3
-
(iv) 2P > M => Presence of OH
-
& CO 3
2-
(v) 2P < M => Presence of HCO 3
-
& CO 3
2-

(Mixture of OH
-
& HCO3
-
is not listed since they do not exist together and are considered equivalent to CO 3
2-
).

PROCEDURE
TITRATION
ESTIMATION OF ALKALINITY IN WATER SAMPLE

Exactly 20 ml of water sample is pipetted out into a clean conical flask. Few drops of phenolphthalein
indicator are added and titrated against a standardized HCl taken in the burette. The end point is the
disappearance of pink colour, which is noted as P. Few drops of methyl orange indicator is added to the same
solution. The solution turns to yellow. The titration is continued further by adding same HCl without break till the
end point is reached. The end point is the colour change from yellow to reddish orange.

The experiment is repeated to get concordant values. From the magnitudes of P & M values, the type of
alkalinity present in the water sample is inferred and the individual amounts are calculated and reported.










12


Carbonate ion alkalinity

Volume of HCl 2 (M ? P) = ??? ????????ml

Strength of HCl = ??.?????..???...N

Volume of water sample =........................................ml

Strength of water sample = Volume of HCl 2 (M ? P) x Strength of HCl
Volume of water sample

= ???????????.. N




? Carbonate ion alkalinity
in terms of CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ???????????mg/l

















13





RESULT

1) The type of alkalinity present in the water sample = -------------------------ions.

2) The individual amounts of alkalinity present in the water sample:
Hydroxide ion alkalinity

= ----------------- ppm
Carbonate ion alkalinity = ------------------ ppm
Bicarbonate ion alkalinity = ----------------- ppm





VIVA-VOCE


1. What is meant by alkalinity?
2. What are the ions responsible for alkalinity?
3. Why OH
-
and HCO 3
?
ions cannot exist together in water?
4. What are the ions responsible for alkalinity when 2P > M?
5. What is the pH range for both in acidic and basic solutions?
6. What is the colour of phenolphthalein in an acid and in an alkaline solution?
7. What is the purpose of using two indicators in same titration?
8. What are the possible combinations of ions for alkalinity?
9. How is the amount of alkalinity expressed?
10. What are the types of indicator used in this experiment?







14

SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II TITRATION III
Standardisation of
EDTA
(EDTA Vs Std
Hard water)
Determination of
total hardness
(Std EDTA Vs Hard
water sample)
Determination of
permanent hardness
(Std EDTA Vs Boiled
Hard water sample)

Burette solution

EDTA solution

EDTA solution

EDTA solution

Pipette solution

20ml Std. hard water

20 ml hard water sample

20ml boiled hard water sample

Indicator

2 drops of EBT

2 drops of EBT

2 drops of EBT

Additional soln.


Ammoniacal Buffer
solution (5ml)

Ammoniacal Buffer solution
(5ml)

Ammoniacal Buffer solution
(5ml)
End point Wine - red to Steel blue Wine - red to steel blue Wine - red to Steel blue




STANDARDISATION OF EDTA
Titration - I
Std. HARD WATER Vs EDTA Indicator: EBT

S. No.
Volume of std hard
water (ml)
Burette Reading Volume of
EDTA
(V 1) (ml)
Concordant value

Initial

Final



Volume of std .hard water taken = 20 ml
Volume of EDTA consumed (V 1) = --------------- ml
1 ml of std.hard water = 1mg of CaCO 3
20 ml of std hard water = 20 mg of CaCO 3

V 1 ml of EDTA solution containing 20 mg of CaCO 3
1 ml of EDTA solution = 20 / V 1 mg of CaCO 3
= -----------------------mg of CaCO 3


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?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





3


PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)
1. Fundamentals
To provide students with a solid foundation in Mathematics, Science and fundamentals of engineering,
enabling them to apply, to find solutions for engineering problems and use this knowledge to acquire higher
education
2. Core Competence
To train the students in chemistry practicals so that they apply their knowledge and training to compare,
and to analyze various engineering industrial problems to find solutions
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice this enables
them to find solutions for the real time problems in industry, and to design products
4. Professionalism
To inculcate professional and effective communication skills, leadership qualities and team spirit in the
students to make them multi-faceted personalities and develop their ability to relate engineering issues to
broader social context
5. Lifelong Learning/Ethics
To demonstrate and practice ethical and professional responsibilities in the industry and society in the
large, through commitment and lifelong learning needed for successful professional career






4


PROGRAMME OUTCOMES (POs)
To demonstrate and apply knowledge of Mathematics, Science and engineering fundamentals in the following
experiments.
1 .To estimate HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. To determine total, temporary & permanent hardness of water by EDTA method.
3. To determine DO content of water sample by Winkler?s method.
4. To determine chloride content of water sample by Argentometric method.
5. To estimate copper content of the given solution by Iodometry.
6. To determine strength of given hydrochloric acid using pH meter.
7. To determine strength of acids in a mixture of acids using conductivity meter.
8. To determine iron content of the given solution using potentiometer.
9. To estimate iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. To estimate sodium and potassium present in water using flame photometer.
11. To determine molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. To determine Pseudo first order kinetics ? ester hydrolysis.
13. To determine Corrosion experiment ? weight loss method.
14. To estimate CMC.
15. To estimate Phase change in a solid.
16. To determine strength of strong acid vs strong base using conductivity meter.











5

BS8161 - CHEMISTRY LABORATORY
SYLLABUS


? To make the student to acquire practical skills in the determination of water quality
parameters through volumetric and instrumental analysis.

? ???? ??? ???? ?? ???? ? ? ?To acquaint the students with the determination of molecular weight of a polymer by
viscometery.

LIST OF EXPERIMENTS:
1. Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. Determination of total, temporary & permanent hardness of water by EDTA method.
3. Determination of DO content of water sample by Winkler?s method.
4. Determination of chloride content of water sample by Argentometric method.
5. Estimation of copper content of the given solution by Iodometry.
6. Determination of strength of given hydrochloric acid using pH meter.
7. Determination of strength of acids in a mixture of acids using conductivity meter.
8. Estimation of iron content of the given solution using potentiometer.
9. Estimation of iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. Estimation of sodium and potassium present in water using flame photometer.
11. Determination of molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. Pseudo first order kinetics ? ester hydrolysis.
13. Corrosion experiment ? weight loss method.
14. Determination of CMC.
15. Phase change in a solid.
16. Conductometric titration of strong acid vs strong base.




? The students will be outfitted with hands-on knowledge in the quantitative chemical
analysis of water quality related parameters.
COURSE OBJECTIVES
COURSE OUTCOMES
6


INDEX [ SEMESTER ? I ]


S.No.



Date


Experiment

Date of
submission



Mark


Signature

1.

Estimation of HCl using Na 2CO 3 as
primary standard and Determination of
alkalinity in water sample.



2.


Determination of total, temporary &
permanent hardness of water by EDTA
method.



3.


Determination of chloride content of water
sample by argentometric method.



4.


Determination of strength of given
hydrochloric acid using pH meter.



5.


Determination of strength of acids in a
mixture of acids using conductivity meter.



6.


Estimation of iron content of the given
solution using potentiometer.



7.





Conductometric titration of strong acid Vs
strong base.



8.



Estimation of copper content of the given
solution by Iodometry


9.
Estimation of sodium and potassium
present in water using flame photometer




7




CONTENTS


S.No.


NAME OF EXPERIMENT

PAGE
No.
SEMESTER - I
1.
Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in
water sample.
09
2. Determination of total, temporary & permanent hardness of water by EDTA method. 15
3. Determination of chloride content of water sample by Argentometric method. 21
4. Determination of strength of given hydrochloric acid using pH meter. 25
5. Determination of strength of acids in a mixture of acids using conductivity meter. 29
6. Estimation of iron content of the given solution using potentiometer. 33
7. Conductometric titration of strong acid Vs strong base.

39


42

8


Estimation of copper content of the given solution by Iodometry 43
9 Estimation of sodium and potassium present in water using flame photometer 47






8



SHORT PROCEDURE:

CONTENTS
TITRATION
Estimation of alkalinity in water sample
(Std HCl Vs water sample)

Burette solution

Std. HCl


Pipette solution

Water sample


Indicator


(i) Phenolphthalein
(ii) Methyl orange


End point

(i) Disappearance of pink colour
(ii) Appearance of reddish orange colour






Relationship
between P &M
Nature of alkalinity
Amount of individual
alkalinities
OH
-
HCO 3
-


CO 3
2-

P = M

only OH
-

P or M

?
0.0

0.0


2P = M

only CO 3
2-


2P or M


0.0


0.0


?

P =0, M?0

only HCO 3
-



M



0.0



?

0.0


2P > M


OH
-
&CO 3
2-


OH
-
= 2P-M
CO 3
2-
= 2(M-P)


?

0.0

?

P < ? M




HCO 3
-
&CO 3
2-


HCO 3
-
= M-2P
CO 3
2-
= 2P

0.0 ? ?




9





Expt. No. 1 DETERMINATION OF ALKALINITY IN WATER
AIM
To determine the type and amounts of alkalinity in the given water sample. A standard solution of Na 2CO 3
of strength ____N is given.

PRINCIPLE
Alkalinity in water is due to the presence of soluble hydroxides, bicarbonates and carbonates.
Determination of various types and amounts of alkalinity is easily carried out by titration with standard HCl
employing the indicators phenolphthalein and methyl orange independently or in succession.

The following reactions occur when different types of alkalinity are neutralized with acid.

OH
?
+ H
+
? H 2O completed at pH 8.2-9.0 ----- (1)

CO 3
2 ?
+ H
+
? HCO 3
?
----- (2)

HCO 3
?
+ H
+
? (H 2CO 3) ? H 2O + CO 2, completed at pH 4.2-5.5 ----- (3)

Neutralisation (1) & (2) will be notified by phenolphthalein end-point while all the three will be

accounted by
methyl orange end-point. Bicarbonate in eqn. (3) may be due to the existence of soluble free bicarbonate salts and
bicarbonates resulting from half neutralization of soluble carbonates (eqn. (2))

Various steps to be followed

a) A known volume of water sample is titrated against std. HCl using first phenolphthalein indicator till
end-point (P) and the titration is continued without break using methyl orange indicator till the end-
point (M).



10


Titration

Estimation of Alkalinity in water sample

Standard HCl Vs Water sample Indicator: 1. Phenolphthalein
2. Methyl Orange


S.No.
Volume
of water
sample (ml)
Burette Reading
Concordant value

Initial Phenolphthalein End
Point (P)
Methyl Orange End
Point (M)

1

2






CALCULATION

Hydroxide ion alkalinity
Volume of HCl (2P-M) = ???????ml

Strength of HCl = ???????? N

Volume of water sample = ???????...ml

Strength of water sample = Volume of HCl (2P-M) x Strength of HCl
Volume of water sample

=

? Hydroxide ion alkalinity in terms of
CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ??????.mg/l







11




b) From the magnitudes of the P & M, the nature of alkalinity can be arrived as follows:

(i) P = M => Presence of only OH
-

(ii) 2P = M => Presence of only CO 3
2-

(iii) P =0, M=0 => Presence of only HCO 3
-
(iv) 2P > M => Presence of OH
-
& CO 3
2-
(v) 2P < M => Presence of HCO 3
-
& CO 3
2-

(Mixture of OH
-
& HCO3
-
is not listed since they do not exist together and are considered equivalent to CO 3
2-
).

PROCEDURE
TITRATION
ESTIMATION OF ALKALINITY IN WATER SAMPLE

Exactly 20 ml of water sample is pipetted out into a clean conical flask. Few drops of phenolphthalein
indicator are added and titrated against a standardized HCl taken in the burette. The end point is the
disappearance of pink colour, which is noted as P. Few drops of methyl orange indicator is added to the same
solution. The solution turns to yellow. The titration is continued further by adding same HCl without break till the
end point is reached. The end point is the colour change from yellow to reddish orange.

The experiment is repeated to get concordant values. From the magnitudes of P & M values, the type of
alkalinity present in the water sample is inferred and the individual amounts are calculated and reported.










12


Carbonate ion alkalinity

Volume of HCl 2 (M ? P) = ??? ????????ml

Strength of HCl = ??.?????..???...N

Volume of water sample =........................................ml

Strength of water sample = Volume of HCl 2 (M ? P) x Strength of HCl
Volume of water sample

= ???????????.. N




? Carbonate ion alkalinity
in terms of CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ???????????mg/l

















13





RESULT

1) The type of alkalinity present in the water sample = -------------------------ions.

2) The individual amounts of alkalinity present in the water sample:
Hydroxide ion alkalinity

= ----------------- ppm
Carbonate ion alkalinity = ------------------ ppm
Bicarbonate ion alkalinity = ----------------- ppm





VIVA-VOCE


1. What is meant by alkalinity?
2. What are the ions responsible for alkalinity?
3. Why OH
-
and HCO 3
?
ions cannot exist together in water?
4. What are the ions responsible for alkalinity when 2P > M?
5. What is the pH range for both in acidic and basic solutions?
6. What is the colour of phenolphthalein in an acid and in an alkaline solution?
7. What is the purpose of using two indicators in same titration?
8. What are the possible combinations of ions for alkalinity?
9. How is the amount of alkalinity expressed?
10. What are the types of indicator used in this experiment?







14

SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II TITRATION III
Standardisation of
EDTA
(EDTA Vs Std
Hard water)
Determination of
total hardness
(Std EDTA Vs Hard
water sample)
Determination of
permanent hardness
(Std EDTA Vs Boiled
Hard water sample)

Burette solution

EDTA solution

EDTA solution

EDTA solution

Pipette solution

20ml Std. hard water

20 ml hard water sample

20ml boiled hard water sample

Indicator

2 drops of EBT

2 drops of EBT

2 drops of EBT

Additional soln.


Ammoniacal Buffer
solution (5ml)

Ammoniacal Buffer solution
(5ml)

Ammoniacal Buffer solution
(5ml)
End point Wine - red to Steel blue Wine - red to steel blue Wine - red to Steel blue




STANDARDISATION OF EDTA
Titration - I
Std. HARD WATER Vs EDTA Indicator: EBT

S. No.
Volume of std hard
water (ml)
Burette Reading Volume of
EDTA
(V 1) (ml)
Concordant value

Initial

Final



Volume of std .hard water taken = 20 ml
Volume of EDTA consumed (V 1) = --------------- ml
1 ml of std.hard water = 1mg of CaCO 3
20 ml of std hard water = 20 mg of CaCO 3

V 1 ml of EDTA solution containing 20 mg of CaCO 3
1 ml of EDTA solution = 20 / V 1 mg of CaCO 3
= -----------------------mg of CaCO 3


15

Expt. No. 2 DETERMINATION OF TOTAL, TEMPORARY AND
PERMANENT HARDNESS OF WATER

AIM
To estimate the amount of total, temporary & permanent hardness in the given sample of water.

PRINCIPLE
The estimation is based on the complexometric titration.

(i) Total hardness of water is estimated by titrating against EDTA using EBT indicator.
EBT+M ?[EBT-M] (unstable complex)
(EBT-M) (Unstable complex) +EDTA ? [EDTA-M] (stable complex) +EBT
EBT indicator forms wine- red colored complex with metal ions present in water. On addition of EDTA
metal ions preferably forms complexes with EDTA and steel blue EBT indicator is set free. Therefore
change of colour from wine- red to steel blue denotes the end point.

(ii) Temporary hardness is removed by boiling the water.
Ca (HCO 3) 2 ? CaCO 3 +CO 2 ?+H 2O
Mg (HCO 3) 2 ? Mg(OH) 2 +2CO 2 ?
The precipitate is filtered and the remaining permanent hardness is estimated using EDTA.

PROCEDURE

TITRATION ? I
STANDARDISATION OF EDTA

Pipette out 20ml of standard hard water into a 250ml conical flask. Add 5ml of buffer solution and 3
drops of eriochrome black T indictor. Titrate the solution with EDTA from the burette until the colour
changes from wine- red to steel blue at the end point. Repeat the titration for concordant values. Let the
titre value be V 1ml.


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?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





3


PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)
1. Fundamentals
To provide students with a solid foundation in Mathematics, Science and fundamentals of engineering,
enabling them to apply, to find solutions for engineering problems and use this knowledge to acquire higher
education
2. Core Competence
To train the students in chemistry practicals so that they apply their knowledge and training to compare,
and to analyze various engineering industrial problems to find solutions
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice this enables
them to find solutions for the real time problems in industry, and to design products
4. Professionalism
To inculcate professional and effective communication skills, leadership qualities and team spirit in the
students to make them multi-faceted personalities and develop their ability to relate engineering issues to
broader social context
5. Lifelong Learning/Ethics
To demonstrate and practice ethical and professional responsibilities in the industry and society in the
large, through commitment and lifelong learning needed for successful professional career






4


PROGRAMME OUTCOMES (POs)
To demonstrate and apply knowledge of Mathematics, Science and engineering fundamentals in the following
experiments.
1 .To estimate HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. To determine total, temporary & permanent hardness of water by EDTA method.
3. To determine DO content of water sample by Winkler?s method.
4. To determine chloride content of water sample by Argentometric method.
5. To estimate copper content of the given solution by Iodometry.
6. To determine strength of given hydrochloric acid using pH meter.
7. To determine strength of acids in a mixture of acids using conductivity meter.
8. To determine iron content of the given solution using potentiometer.
9. To estimate iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. To estimate sodium and potassium present in water using flame photometer.
11. To determine molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. To determine Pseudo first order kinetics ? ester hydrolysis.
13. To determine Corrosion experiment ? weight loss method.
14. To estimate CMC.
15. To estimate Phase change in a solid.
16. To determine strength of strong acid vs strong base using conductivity meter.











5

BS8161 - CHEMISTRY LABORATORY
SYLLABUS


? To make the student to acquire practical skills in the determination of water quality
parameters through volumetric and instrumental analysis.

? ???? ??? ???? ?? ???? ? ? ?To acquaint the students with the determination of molecular weight of a polymer by
viscometery.

LIST OF EXPERIMENTS:
1. Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. Determination of total, temporary & permanent hardness of water by EDTA method.
3. Determination of DO content of water sample by Winkler?s method.
4. Determination of chloride content of water sample by Argentometric method.
5. Estimation of copper content of the given solution by Iodometry.
6. Determination of strength of given hydrochloric acid using pH meter.
7. Determination of strength of acids in a mixture of acids using conductivity meter.
8. Estimation of iron content of the given solution using potentiometer.
9. Estimation of iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. Estimation of sodium and potassium present in water using flame photometer.
11. Determination of molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. Pseudo first order kinetics ? ester hydrolysis.
13. Corrosion experiment ? weight loss method.
14. Determination of CMC.
15. Phase change in a solid.
16. Conductometric titration of strong acid vs strong base.




? The students will be outfitted with hands-on knowledge in the quantitative chemical
analysis of water quality related parameters.
COURSE OBJECTIVES
COURSE OUTCOMES
6


INDEX [ SEMESTER ? I ]


S.No.



Date


Experiment

Date of
submission



Mark


Signature

1.

Estimation of HCl using Na 2CO 3 as
primary standard and Determination of
alkalinity in water sample.



2.


Determination of total, temporary &
permanent hardness of water by EDTA
method.



3.


Determination of chloride content of water
sample by argentometric method.



4.


Determination of strength of given
hydrochloric acid using pH meter.



5.


Determination of strength of acids in a
mixture of acids using conductivity meter.



6.


Estimation of iron content of the given
solution using potentiometer.



7.





Conductometric titration of strong acid Vs
strong base.



8.



Estimation of copper content of the given
solution by Iodometry


9.
Estimation of sodium and potassium
present in water using flame photometer




7




CONTENTS


S.No.


NAME OF EXPERIMENT

PAGE
No.
SEMESTER - I
1.
Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in
water sample.
09
2. Determination of total, temporary & permanent hardness of water by EDTA method. 15
3. Determination of chloride content of water sample by Argentometric method. 21
4. Determination of strength of given hydrochloric acid using pH meter. 25
5. Determination of strength of acids in a mixture of acids using conductivity meter. 29
6. Estimation of iron content of the given solution using potentiometer. 33
7. Conductometric titration of strong acid Vs strong base.

39


42

8


Estimation of copper content of the given solution by Iodometry 43
9 Estimation of sodium and potassium present in water using flame photometer 47






8



SHORT PROCEDURE:

CONTENTS
TITRATION
Estimation of alkalinity in water sample
(Std HCl Vs water sample)

Burette solution

Std. HCl


Pipette solution

Water sample


Indicator


(i) Phenolphthalein
(ii) Methyl orange


End point

(i) Disappearance of pink colour
(ii) Appearance of reddish orange colour






Relationship
between P &M
Nature of alkalinity
Amount of individual
alkalinities
OH
-
HCO 3
-


CO 3
2-

P = M

only OH
-

P or M

?
0.0

0.0


2P = M

only CO 3
2-


2P or M


0.0


0.0


?

P =0, M?0

only HCO 3
-



M



0.0



?

0.0


2P > M


OH
-
&CO 3
2-


OH
-
= 2P-M
CO 3
2-
= 2(M-P)


?

0.0

?

P < ? M




HCO 3
-
&CO 3
2-


HCO 3
-
= M-2P
CO 3
2-
= 2P

0.0 ? ?




9





Expt. No. 1 DETERMINATION OF ALKALINITY IN WATER
AIM
To determine the type and amounts of alkalinity in the given water sample. A standard solution of Na 2CO 3
of strength ____N is given.

PRINCIPLE
Alkalinity in water is due to the presence of soluble hydroxides, bicarbonates and carbonates.
Determination of various types and amounts of alkalinity is easily carried out by titration with standard HCl
employing the indicators phenolphthalein and methyl orange independently or in succession.

The following reactions occur when different types of alkalinity are neutralized with acid.

OH
?
+ H
+
? H 2O completed at pH 8.2-9.0 ----- (1)

CO 3
2 ?
+ H
+
? HCO 3
?
----- (2)

HCO 3
?
+ H
+
? (H 2CO 3) ? H 2O + CO 2, completed at pH 4.2-5.5 ----- (3)

Neutralisation (1) & (2) will be notified by phenolphthalein end-point while all the three will be

accounted by
methyl orange end-point. Bicarbonate in eqn. (3) may be due to the existence of soluble free bicarbonate salts and
bicarbonates resulting from half neutralization of soluble carbonates (eqn. (2))

Various steps to be followed

a) A known volume of water sample is titrated against std. HCl using first phenolphthalein indicator till
end-point (P) and the titration is continued without break using methyl orange indicator till the end-
point (M).



10


Titration

Estimation of Alkalinity in water sample

Standard HCl Vs Water sample Indicator: 1. Phenolphthalein
2. Methyl Orange


S.No.
Volume
of water
sample (ml)
Burette Reading
Concordant value

Initial Phenolphthalein End
Point (P)
Methyl Orange End
Point (M)

1

2






CALCULATION

Hydroxide ion alkalinity
Volume of HCl (2P-M) = ???????ml

Strength of HCl = ???????? N

Volume of water sample = ???????...ml

Strength of water sample = Volume of HCl (2P-M) x Strength of HCl
Volume of water sample

=

? Hydroxide ion alkalinity in terms of
CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ??????.mg/l







11




b) From the magnitudes of the P & M, the nature of alkalinity can be arrived as follows:

(i) P = M => Presence of only OH
-

(ii) 2P = M => Presence of only CO 3
2-

(iii) P =0, M=0 => Presence of only HCO 3
-
(iv) 2P > M => Presence of OH
-
& CO 3
2-
(v) 2P < M => Presence of HCO 3
-
& CO 3
2-

(Mixture of OH
-
& HCO3
-
is not listed since they do not exist together and are considered equivalent to CO 3
2-
).

PROCEDURE
TITRATION
ESTIMATION OF ALKALINITY IN WATER SAMPLE

Exactly 20 ml of water sample is pipetted out into a clean conical flask. Few drops of phenolphthalein
indicator are added and titrated against a standardized HCl taken in the burette. The end point is the
disappearance of pink colour, which is noted as P. Few drops of methyl orange indicator is added to the same
solution. The solution turns to yellow. The titration is continued further by adding same HCl without break till the
end point is reached. The end point is the colour change from yellow to reddish orange.

The experiment is repeated to get concordant values. From the magnitudes of P & M values, the type of
alkalinity present in the water sample is inferred and the individual amounts are calculated and reported.










12


Carbonate ion alkalinity

Volume of HCl 2 (M ? P) = ??? ????????ml

Strength of HCl = ??.?????..???...N

Volume of water sample =........................................ml

Strength of water sample = Volume of HCl 2 (M ? P) x Strength of HCl
Volume of water sample

= ???????????.. N




? Carbonate ion alkalinity
in terms of CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ???????????mg/l

















13





RESULT

1) The type of alkalinity present in the water sample = -------------------------ions.

2) The individual amounts of alkalinity present in the water sample:
Hydroxide ion alkalinity

= ----------------- ppm
Carbonate ion alkalinity = ------------------ ppm
Bicarbonate ion alkalinity = ----------------- ppm





VIVA-VOCE


1. What is meant by alkalinity?
2. What are the ions responsible for alkalinity?
3. Why OH
-
and HCO 3
?
ions cannot exist together in water?
4. What are the ions responsible for alkalinity when 2P > M?
5. What is the pH range for both in acidic and basic solutions?
6. What is the colour of phenolphthalein in an acid and in an alkaline solution?
7. What is the purpose of using two indicators in same titration?
8. What are the possible combinations of ions for alkalinity?
9. How is the amount of alkalinity expressed?
10. What are the types of indicator used in this experiment?







14

SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II TITRATION III
Standardisation of
EDTA
(EDTA Vs Std
Hard water)
Determination of
total hardness
(Std EDTA Vs Hard
water sample)
Determination of
permanent hardness
(Std EDTA Vs Boiled
Hard water sample)

Burette solution

EDTA solution

EDTA solution

EDTA solution

Pipette solution

20ml Std. hard water

20 ml hard water sample

20ml boiled hard water sample

Indicator

2 drops of EBT

2 drops of EBT

2 drops of EBT

Additional soln.


Ammoniacal Buffer
solution (5ml)

Ammoniacal Buffer solution
(5ml)

Ammoniacal Buffer solution
(5ml)
End point Wine - red to Steel blue Wine - red to steel blue Wine - red to Steel blue




STANDARDISATION OF EDTA
Titration - I
Std. HARD WATER Vs EDTA Indicator: EBT

S. No.
Volume of std hard
water (ml)
Burette Reading Volume of
EDTA
(V 1) (ml)
Concordant value

Initial

Final



Volume of std .hard water taken = 20 ml
Volume of EDTA consumed (V 1) = --------------- ml
1 ml of std.hard water = 1mg of CaCO 3
20 ml of std hard water = 20 mg of CaCO 3

V 1 ml of EDTA solution containing 20 mg of CaCO 3
1 ml of EDTA solution = 20 / V 1 mg of CaCO 3
= -----------------------mg of CaCO 3


15

Expt. No. 2 DETERMINATION OF TOTAL, TEMPORARY AND
PERMANENT HARDNESS OF WATER

AIM
To estimate the amount of total, temporary & permanent hardness in the given sample of water.

PRINCIPLE
The estimation is based on the complexometric titration.

(i) Total hardness of water is estimated by titrating against EDTA using EBT indicator.
EBT+M ?[EBT-M] (unstable complex)
(EBT-M) (Unstable complex) +EDTA ? [EDTA-M] (stable complex) +EBT
EBT indicator forms wine- red colored complex with metal ions present in water. On addition of EDTA
metal ions preferably forms complexes with EDTA and steel blue EBT indicator is set free. Therefore
change of colour from wine- red to steel blue denotes the end point.

(ii) Temporary hardness is removed by boiling the water.
Ca (HCO 3) 2 ? CaCO 3 +CO 2 ?+H 2O
Mg (HCO 3) 2 ? Mg(OH) 2 +2CO 2 ?
The precipitate is filtered and the remaining permanent hardness is estimated using EDTA.

PROCEDURE

TITRATION ? I
STANDARDISATION OF EDTA

Pipette out 20ml of standard hard water into a 250ml conical flask. Add 5ml of buffer solution and 3
drops of eriochrome black T indictor. Titrate the solution with EDTA from the burette until the colour
changes from wine- red to steel blue at the end point. Repeat the titration for concordant values. Let the
titre value be V 1ml.


16


Titration-II
SAMPLE HARD WATER Vs Std EDTA Indicator: EBT

S.No. Volume of sample
hard water (ml)
Burette Reading Volume of
EDTA
(V 2) (ml)
Concordant value

Initial

Final




CALCULATION

Calculation of total hardness


Volume of EDTA consumed (V 2) = ------------------------- ml
1ml of EDTA = 20 / V 1 mg of CaCO 3
V 2 ml of EDTA = 20 / V 1 x V 2 mg of CaCO 3

( i.e), If 20ml of sample hard water contains 20 x V 2 mg of CaCO 3 / V 1

Then 1000ml of water sample = 20 x V 2 x 1000 / V 1 x 20 mg of CaCO 3

= 1000 x V 2 / V 1 mg of CaCO3

Total hardness of given water sample = ---------------------ppm









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?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





3


PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)
1. Fundamentals
To provide students with a solid foundation in Mathematics, Science and fundamentals of engineering,
enabling them to apply, to find solutions for engineering problems and use this knowledge to acquire higher
education
2. Core Competence
To train the students in chemistry practicals so that they apply their knowledge and training to compare,
and to analyze various engineering industrial problems to find solutions
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice this enables
them to find solutions for the real time problems in industry, and to design products
4. Professionalism
To inculcate professional and effective communication skills, leadership qualities and team spirit in the
students to make them multi-faceted personalities and develop their ability to relate engineering issues to
broader social context
5. Lifelong Learning/Ethics
To demonstrate and practice ethical and professional responsibilities in the industry and society in the
large, through commitment and lifelong learning needed for successful professional career






4


PROGRAMME OUTCOMES (POs)
To demonstrate and apply knowledge of Mathematics, Science and engineering fundamentals in the following
experiments.
1 .To estimate HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. To determine total, temporary & permanent hardness of water by EDTA method.
3. To determine DO content of water sample by Winkler?s method.
4. To determine chloride content of water sample by Argentometric method.
5. To estimate copper content of the given solution by Iodometry.
6. To determine strength of given hydrochloric acid using pH meter.
7. To determine strength of acids in a mixture of acids using conductivity meter.
8. To determine iron content of the given solution using potentiometer.
9. To estimate iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. To estimate sodium and potassium present in water using flame photometer.
11. To determine molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. To determine Pseudo first order kinetics ? ester hydrolysis.
13. To determine Corrosion experiment ? weight loss method.
14. To estimate CMC.
15. To estimate Phase change in a solid.
16. To determine strength of strong acid vs strong base using conductivity meter.











5

BS8161 - CHEMISTRY LABORATORY
SYLLABUS


? To make the student to acquire practical skills in the determination of water quality
parameters through volumetric and instrumental analysis.

? ???? ??? ???? ?? ???? ? ? ?To acquaint the students with the determination of molecular weight of a polymer by
viscometery.

LIST OF EXPERIMENTS:
1. Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. Determination of total, temporary & permanent hardness of water by EDTA method.
3. Determination of DO content of water sample by Winkler?s method.
4. Determination of chloride content of water sample by Argentometric method.
5. Estimation of copper content of the given solution by Iodometry.
6. Determination of strength of given hydrochloric acid using pH meter.
7. Determination of strength of acids in a mixture of acids using conductivity meter.
8. Estimation of iron content of the given solution using potentiometer.
9. Estimation of iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. Estimation of sodium and potassium present in water using flame photometer.
11. Determination of molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. Pseudo first order kinetics ? ester hydrolysis.
13. Corrosion experiment ? weight loss method.
14. Determination of CMC.
15. Phase change in a solid.
16. Conductometric titration of strong acid vs strong base.




? The students will be outfitted with hands-on knowledge in the quantitative chemical
analysis of water quality related parameters.
COURSE OBJECTIVES
COURSE OUTCOMES
6


INDEX [ SEMESTER ? I ]


S.No.



Date


Experiment

Date of
submission



Mark


Signature

1.

Estimation of HCl using Na 2CO 3 as
primary standard and Determination of
alkalinity in water sample.



2.


Determination of total, temporary &
permanent hardness of water by EDTA
method.



3.


Determination of chloride content of water
sample by argentometric method.



4.


Determination of strength of given
hydrochloric acid using pH meter.



5.


Determination of strength of acids in a
mixture of acids using conductivity meter.



6.


Estimation of iron content of the given
solution using potentiometer.



7.





Conductometric titration of strong acid Vs
strong base.



8.



Estimation of copper content of the given
solution by Iodometry


9.
Estimation of sodium and potassium
present in water using flame photometer




7




CONTENTS


S.No.


NAME OF EXPERIMENT

PAGE
No.
SEMESTER - I
1.
Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in
water sample.
09
2. Determination of total, temporary & permanent hardness of water by EDTA method. 15
3. Determination of chloride content of water sample by Argentometric method. 21
4. Determination of strength of given hydrochloric acid using pH meter. 25
5. Determination of strength of acids in a mixture of acids using conductivity meter. 29
6. Estimation of iron content of the given solution using potentiometer. 33
7. Conductometric titration of strong acid Vs strong base.

39


42

8


Estimation of copper content of the given solution by Iodometry 43
9 Estimation of sodium and potassium present in water using flame photometer 47






8



SHORT PROCEDURE:

CONTENTS
TITRATION
Estimation of alkalinity in water sample
(Std HCl Vs water sample)

Burette solution

Std. HCl


Pipette solution

Water sample


Indicator


(i) Phenolphthalein
(ii) Methyl orange


End point

(i) Disappearance of pink colour
(ii) Appearance of reddish orange colour






Relationship
between P &M
Nature of alkalinity
Amount of individual
alkalinities
OH
-
HCO 3
-


CO 3
2-

P = M

only OH
-

P or M

?
0.0

0.0


2P = M

only CO 3
2-


2P or M


0.0


0.0


?

P =0, M?0

only HCO 3
-



M



0.0



?

0.0


2P > M


OH
-
&CO 3
2-


OH
-
= 2P-M
CO 3
2-
= 2(M-P)


?

0.0

?

P < ? M




HCO 3
-
&CO 3
2-


HCO 3
-
= M-2P
CO 3
2-
= 2P

0.0 ? ?




9





Expt. No. 1 DETERMINATION OF ALKALINITY IN WATER
AIM
To determine the type and amounts of alkalinity in the given water sample. A standard solution of Na 2CO 3
of strength ____N is given.

PRINCIPLE
Alkalinity in water is due to the presence of soluble hydroxides, bicarbonates and carbonates.
Determination of various types and amounts of alkalinity is easily carried out by titration with standard HCl
employing the indicators phenolphthalein and methyl orange independently or in succession.

The following reactions occur when different types of alkalinity are neutralized with acid.

OH
?
+ H
+
? H 2O completed at pH 8.2-9.0 ----- (1)

CO 3
2 ?
+ H
+
? HCO 3
?
----- (2)

HCO 3
?
+ H
+
? (H 2CO 3) ? H 2O + CO 2, completed at pH 4.2-5.5 ----- (3)

Neutralisation (1) & (2) will be notified by phenolphthalein end-point while all the three will be

accounted by
methyl orange end-point. Bicarbonate in eqn. (3) may be due to the existence of soluble free bicarbonate salts and
bicarbonates resulting from half neutralization of soluble carbonates (eqn. (2))

Various steps to be followed

a) A known volume of water sample is titrated against std. HCl using first phenolphthalein indicator till
end-point (P) and the titration is continued without break using methyl orange indicator till the end-
point (M).



10


Titration

Estimation of Alkalinity in water sample

Standard HCl Vs Water sample Indicator: 1. Phenolphthalein
2. Methyl Orange


S.No.
Volume
of water
sample (ml)
Burette Reading
Concordant value

Initial Phenolphthalein End
Point (P)
Methyl Orange End
Point (M)

1

2






CALCULATION

Hydroxide ion alkalinity
Volume of HCl (2P-M) = ???????ml

Strength of HCl = ???????? N

Volume of water sample = ???????...ml

Strength of water sample = Volume of HCl (2P-M) x Strength of HCl
Volume of water sample

=

? Hydroxide ion alkalinity in terms of
CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ??????.mg/l







11




b) From the magnitudes of the P & M, the nature of alkalinity can be arrived as follows:

(i) P = M => Presence of only OH
-

(ii) 2P = M => Presence of only CO 3
2-

(iii) P =0, M=0 => Presence of only HCO 3
-
(iv) 2P > M => Presence of OH
-
& CO 3
2-
(v) 2P < M => Presence of HCO 3
-
& CO 3
2-

(Mixture of OH
-
& HCO3
-
is not listed since they do not exist together and are considered equivalent to CO 3
2-
).

PROCEDURE
TITRATION
ESTIMATION OF ALKALINITY IN WATER SAMPLE

Exactly 20 ml of water sample is pipetted out into a clean conical flask. Few drops of phenolphthalein
indicator are added and titrated against a standardized HCl taken in the burette. The end point is the
disappearance of pink colour, which is noted as P. Few drops of methyl orange indicator is added to the same
solution. The solution turns to yellow. The titration is continued further by adding same HCl without break till the
end point is reached. The end point is the colour change from yellow to reddish orange.

The experiment is repeated to get concordant values. From the magnitudes of P & M values, the type of
alkalinity present in the water sample is inferred and the individual amounts are calculated and reported.










12


Carbonate ion alkalinity

Volume of HCl 2 (M ? P) = ??? ????????ml

Strength of HCl = ??.?????..???...N

Volume of water sample =........................................ml

Strength of water sample = Volume of HCl 2 (M ? P) x Strength of HCl
Volume of water sample

= ???????????.. N




? Carbonate ion alkalinity
in terms of CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ???????????mg/l

















13





RESULT

1) The type of alkalinity present in the water sample = -------------------------ions.

2) The individual amounts of alkalinity present in the water sample:
Hydroxide ion alkalinity

= ----------------- ppm
Carbonate ion alkalinity = ------------------ ppm
Bicarbonate ion alkalinity = ----------------- ppm





VIVA-VOCE


1. What is meant by alkalinity?
2. What are the ions responsible for alkalinity?
3. Why OH
-
and HCO 3
?
ions cannot exist together in water?
4. What are the ions responsible for alkalinity when 2P > M?
5. What is the pH range for both in acidic and basic solutions?
6. What is the colour of phenolphthalein in an acid and in an alkaline solution?
7. What is the purpose of using two indicators in same titration?
8. What are the possible combinations of ions for alkalinity?
9. How is the amount of alkalinity expressed?
10. What are the types of indicator used in this experiment?







14

SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II TITRATION III
Standardisation of
EDTA
(EDTA Vs Std
Hard water)
Determination of
total hardness
(Std EDTA Vs Hard
water sample)
Determination of
permanent hardness
(Std EDTA Vs Boiled
Hard water sample)

Burette solution

EDTA solution

EDTA solution

EDTA solution

Pipette solution

20ml Std. hard water

20 ml hard water sample

20ml boiled hard water sample

Indicator

2 drops of EBT

2 drops of EBT

2 drops of EBT

Additional soln.


Ammoniacal Buffer
solution (5ml)

Ammoniacal Buffer solution
(5ml)

Ammoniacal Buffer solution
(5ml)
End point Wine - red to Steel blue Wine - red to steel blue Wine - red to Steel blue




STANDARDISATION OF EDTA
Titration - I
Std. HARD WATER Vs EDTA Indicator: EBT

S. No.
Volume of std hard
water (ml)
Burette Reading Volume of
EDTA
(V 1) (ml)
Concordant value

Initial

Final



Volume of std .hard water taken = 20 ml
Volume of EDTA consumed (V 1) = --------------- ml
1 ml of std.hard water = 1mg of CaCO 3
20 ml of std hard water = 20 mg of CaCO 3

V 1 ml of EDTA solution containing 20 mg of CaCO 3
1 ml of EDTA solution = 20 / V 1 mg of CaCO 3
= -----------------------mg of CaCO 3


15

Expt. No. 2 DETERMINATION OF TOTAL, TEMPORARY AND
PERMANENT HARDNESS OF WATER

AIM
To estimate the amount of total, temporary & permanent hardness in the given sample of water.

PRINCIPLE
The estimation is based on the complexometric titration.

(i) Total hardness of water is estimated by titrating against EDTA using EBT indicator.
EBT+M ?[EBT-M] (unstable complex)
(EBT-M) (Unstable complex) +EDTA ? [EDTA-M] (stable complex) +EBT
EBT indicator forms wine- red colored complex with metal ions present in water. On addition of EDTA
metal ions preferably forms complexes with EDTA and steel blue EBT indicator is set free. Therefore
change of colour from wine- red to steel blue denotes the end point.

(ii) Temporary hardness is removed by boiling the water.
Ca (HCO 3) 2 ? CaCO 3 +CO 2 ?+H 2O
Mg (HCO 3) 2 ? Mg(OH) 2 +2CO 2 ?
The precipitate is filtered and the remaining permanent hardness is estimated using EDTA.

PROCEDURE

TITRATION ? I
STANDARDISATION OF EDTA

Pipette out 20ml of standard hard water into a 250ml conical flask. Add 5ml of buffer solution and 3
drops of eriochrome black T indictor. Titrate the solution with EDTA from the burette until the colour
changes from wine- red to steel blue at the end point. Repeat the titration for concordant values. Let the
titre value be V 1ml.


16


Titration-II
SAMPLE HARD WATER Vs Std EDTA Indicator: EBT

S.No. Volume of sample
hard water (ml)
Burette Reading Volume of
EDTA
(V 2) (ml)
Concordant value

Initial

Final




CALCULATION

Calculation of total hardness


Volume of EDTA consumed (V 2) = ------------------------- ml
1ml of EDTA = 20 / V 1 mg of CaCO 3
V 2 ml of EDTA = 20 / V 1 x V 2 mg of CaCO 3

( i.e), If 20ml of sample hard water contains 20 x V 2 mg of CaCO 3 / V 1

Then 1000ml of water sample = 20 x V 2 x 1000 / V 1 x 20 mg of CaCO 3

= 1000 x V 2 / V 1 mg of CaCO3

Total hardness of given water sample = ---------------------ppm









17



DETERMINATION OF TOTAL HARDNESS

Pipette out 20ml of sample hard water into a clean conical flask. Add 5ml of buffer solution and 4 -5
drops of Eriochrome black -T indicator. Titrate the wine - red coloured solution with EDTA from the burette until
the colour steel blue appears at the end point. Repeat the titration for concordant values. Let the titre value be
V 2ml.



DETERMINATION OF PERMANENT HARDNESS

Take 100ml of hard water sample in a 500ml beaker and boil gently for about 1hour. Cool, filter it into a
100ml standard flask and make the volume up to the mark. Take 20ml of this solution and proceed it in the same
way as in titration (I). The volume of EDTA consumed corresponds to the permanent hardness of the water
sample. Let the titre value be V 3ml. Temporary hardness is calculated by subtracting permanent hardness from
total hardness.





















FirstRanker.com - FirstRanker's Choice



?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





3


PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)
1. Fundamentals
To provide students with a solid foundation in Mathematics, Science and fundamentals of engineering,
enabling them to apply, to find solutions for engineering problems and use this knowledge to acquire higher
education
2. Core Competence
To train the students in chemistry practicals so that they apply their knowledge and training to compare,
and to analyze various engineering industrial problems to find solutions
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice this enables
them to find solutions for the real time problems in industry, and to design products
4. Professionalism
To inculcate professional and effective communication skills, leadership qualities and team spirit in the
students to make them multi-faceted personalities and develop their ability to relate engineering issues to
broader social context
5. Lifelong Learning/Ethics
To demonstrate and practice ethical and professional responsibilities in the industry and society in the
large, through commitment and lifelong learning needed for successful professional career






4


PROGRAMME OUTCOMES (POs)
To demonstrate and apply knowledge of Mathematics, Science and engineering fundamentals in the following
experiments.
1 .To estimate HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. To determine total, temporary & permanent hardness of water by EDTA method.
3. To determine DO content of water sample by Winkler?s method.
4. To determine chloride content of water sample by Argentometric method.
5. To estimate copper content of the given solution by Iodometry.
6. To determine strength of given hydrochloric acid using pH meter.
7. To determine strength of acids in a mixture of acids using conductivity meter.
8. To determine iron content of the given solution using potentiometer.
9. To estimate iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. To estimate sodium and potassium present in water using flame photometer.
11. To determine molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. To determine Pseudo first order kinetics ? ester hydrolysis.
13. To determine Corrosion experiment ? weight loss method.
14. To estimate CMC.
15. To estimate Phase change in a solid.
16. To determine strength of strong acid vs strong base using conductivity meter.











5

BS8161 - CHEMISTRY LABORATORY
SYLLABUS


? To make the student to acquire practical skills in the determination of water quality
parameters through volumetric and instrumental analysis.

? ???? ??? ???? ?? ???? ? ? ?To acquaint the students with the determination of molecular weight of a polymer by
viscometery.

LIST OF EXPERIMENTS:
1. Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. Determination of total, temporary & permanent hardness of water by EDTA method.
3. Determination of DO content of water sample by Winkler?s method.
4. Determination of chloride content of water sample by Argentometric method.
5. Estimation of copper content of the given solution by Iodometry.
6. Determination of strength of given hydrochloric acid using pH meter.
7. Determination of strength of acids in a mixture of acids using conductivity meter.
8. Estimation of iron content of the given solution using potentiometer.
9. Estimation of iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. Estimation of sodium and potassium present in water using flame photometer.
11. Determination of molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. Pseudo first order kinetics ? ester hydrolysis.
13. Corrosion experiment ? weight loss method.
14. Determination of CMC.
15. Phase change in a solid.
16. Conductometric titration of strong acid vs strong base.




? The students will be outfitted with hands-on knowledge in the quantitative chemical
analysis of water quality related parameters.
COURSE OBJECTIVES
COURSE OUTCOMES
6


INDEX [ SEMESTER ? I ]


S.No.



Date


Experiment

Date of
submission



Mark


Signature

1.

Estimation of HCl using Na 2CO 3 as
primary standard and Determination of
alkalinity in water sample.



2.


Determination of total, temporary &
permanent hardness of water by EDTA
method.



3.


Determination of chloride content of water
sample by argentometric method.



4.


Determination of strength of given
hydrochloric acid using pH meter.



5.


Determination of strength of acids in a
mixture of acids using conductivity meter.



6.


Estimation of iron content of the given
solution using potentiometer.



7.





Conductometric titration of strong acid Vs
strong base.



8.



Estimation of copper content of the given
solution by Iodometry


9.
Estimation of sodium and potassium
present in water using flame photometer




7




CONTENTS


S.No.


NAME OF EXPERIMENT

PAGE
No.
SEMESTER - I
1.
Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in
water sample.
09
2. Determination of total, temporary & permanent hardness of water by EDTA method. 15
3. Determination of chloride content of water sample by Argentometric method. 21
4. Determination of strength of given hydrochloric acid using pH meter. 25
5. Determination of strength of acids in a mixture of acids using conductivity meter. 29
6. Estimation of iron content of the given solution using potentiometer. 33
7. Conductometric titration of strong acid Vs strong base.

39


42

8


Estimation of copper content of the given solution by Iodometry 43
9 Estimation of sodium and potassium present in water using flame photometer 47






8



SHORT PROCEDURE:

CONTENTS
TITRATION
Estimation of alkalinity in water sample
(Std HCl Vs water sample)

Burette solution

Std. HCl


Pipette solution

Water sample


Indicator


(i) Phenolphthalein
(ii) Methyl orange


End point

(i) Disappearance of pink colour
(ii) Appearance of reddish orange colour






Relationship
between P &M
Nature of alkalinity
Amount of individual
alkalinities
OH
-
HCO 3
-


CO 3
2-

P = M

only OH
-

P or M

?
0.0

0.0


2P = M

only CO 3
2-


2P or M


0.0


0.0


?

P =0, M?0

only HCO 3
-



M



0.0



?

0.0


2P > M


OH
-
&CO 3
2-


OH
-
= 2P-M
CO 3
2-
= 2(M-P)


?

0.0

?

P < ? M




HCO 3
-
&CO 3
2-


HCO 3
-
= M-2P
CO 3
2-
= 2P

0.0 ? ?




9





Expt. No. 1 DETERMINATION OF ALKALINITY IN WATER
AIM
To determine the type and amounts of alkalinity in the given water sample. A standard solution of Na 2CO 3
of strength ____N is given.

PRINCIPLE
Alkalinity in water is due to the presence of soluble hydroxides, bicarbonates and carbonates.
Determination of various types and amounts of alkalinity is easily carried out by titration with standard HCl
employing the indicators phenolphthalein and methyl orange independently or in succession.

The following reactions occur when different types of alkalinity are neutralized with acid.

OH
?
+ H
+
? H 2O completed at pH 8.2-9.0 ----- (1)

CO 3
2 ?
+ H
+
? HCO 3
?
----- (2)

HCO 3
?
+ H
+
? (H 2CO 3) ? H 2O + CO 2, completed at pH 4.2-5.5 ----- (3)

Neutralisation (1) & (2) will be notified by phenolphthalein end-point while all the three will be

accounted by
methyl orange end-point. Bicarbonate in eqn. (3) may be due to the existence of soluble free bicarbonate salts and
bicarbonates resulting from half neutralization of soluble carbonates (eqn. (2))

Various steps to be followed

a) A known volume of water sample is titrated against std. HCl using first phenolphthalein indicator till
end-point (P) and the titration is continued without break using methyl orange indicator till the end-
point (M).



10


Titration

Estimation of Alkalinity in water sample

Standard HCl Vs Water sample Indicator: 1. Phenolphthalein
2. Methyl Orange


S.No.
Volume
of water
sample (ml)
Burette Reading
Concordant value

Initial Phenolphthalein End
Point (P)
Methyl Orange End
Point (M)

1

2






CALCULATION

Hydroxide ion alkalinity
Volume of HCl (2P-M) = ???????ml

Strength of HCl = ???????? N

Volume of water sample = ???????...ml

Strength of water sample = Volume of HCl (2P-M) x Strength of HCl
Volume of water sample

=

? Hydroxide ion alkalinity in terms of
CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ??????.mg/l







11




b) From the magnitudes of the P & M, the nature of alkalinity can be arrived as follows:

(i) P = M => Presence of only OH
-

(ii) 2P = M => Presence of only CO 3
2-

(iii) P =0, M=0 => Presence of only HCO 3
-
(iv) 2P > M => Presence of OH
-
& CO 3
2-
(v) 2P < M => Presence of HCO 3
-
& CO 3
2-

(Mixture of OH
-
& HCO3
-
is not listed since they do not exist together and are considered equivalent to CO 3
2-
).

PROCEDURE
TITRATION
ESTIMATION OF ALKALINITY IN WATER SAMPLE

Exactly 20 ml of water sample is pipetted out into a clean conical flask. Few drops of phenolphthalein
indicator are added and titrated against a standardized HCl taken in the burette. The end point is the
disappearance of pink colour, which is noted as P. Few drops of methyl orange indicator is added to the same
solution. The solution turns to yellow. The titration is continued further by adding same HCl without break till the
end point is reached. The end point is the colour change from yellow to reddish orange.

The experiment is repeated to get concordant values. From the magnitudes of P & M values, the type of
alkalinity present in the water sample is inferred and the individual amounts are calculated and reported.










12


Carbonate ion alkalinity

Volume of HCl 2 (M ? P) = ??? ????????ml

Strength of HCl = ??.?????..???...N

Volume of water sample =........................................ml

Strength of water sample = Volume of HCl 2 (M ? P) x Strength of HCl
Volume of water sample

= ???????????.. N




? Carbonate ion alkalinity
in terms of CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ???????????mg/l

















13





RESULT

1) The type of alkalinity present in the water sample = -------------------------ions.

2) The individual amounts of alkalinity present in the water sample:
Hydroxide ion alkalinity

= ----------------- ppm
Carbonate ion alkalinity = ------------------ ppm
Bicarbonate ion alkalinity = ----------------- ppm





VIVA-VOCE


1. What is meant by alkalinity?
2. What are the ions responsible for alkalinity?
3. Why OH
-
and HCO 3
?
ions cannot exist together in water?
4. What are the ions responsible for alkalinity when 2P > M?
5. What is the pH range for both in acidic and basic solutions?
6. What is the colour of phenolphthalein in an acid and in an alkaline solution?
7. What is the purpose of using two indicators in same titration?
8. What are the possible combinations of ions for alkalinity?
9. How is the amount of alkalinity expressed?
10. What are the types of indicator used in this experiment?







14

SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II TITRATION III
Standardisation of
EDTA
(EDTA Vs Std
Hard water)
Determination of
total hardness
(Std EDTA Vs Hard
water sample)
Determination of
permanent hardness
(Std EDTA Vs Boiled
Hard water sample)

Burette solution

EDTA solution

EDTA solution

EDTA solution

Pipette solution

20ml Std. hard water

20 ml hard water sample

20ml boiled hard water sample

Indicator

2 drops of EBT

2 drops of EBT

2 drops of EBT

Additional soln.


Ammoniacal Buffer
solution (5ml)

Ammoniacal Buffer solution
(5ml)

Ammoniacal Buffer solution
(5ml)
End point Wine - red to Steel blue Wine - red to steel blue Wine - red to Steel blue




STANDARDISATION OF EDTA
Titration - I
Std. HARD WATER Vs EDTA Indicator: EBT

S. No.
Volume of std hard
water (ml)
Burette Reading Volume of
EDTA
(V 1) (ml)
Concordant value

Initial

Final



Volume of std .hard water taken = 20 ml
Volume of EDTA consumed (V 1) = --------------- ml
1 ml of std.hard water = 1mg of CaCO 3
20 ml of std hard water = 20 mg of CaCO 3

V 1 ml of EDTA solution containing 20 mg of CaCO 3
1 ml of EDTA solution = 20 / V 1 mg of CaCO 3
= -----------------------mg of CaCO 3


15

Expt. No. 2 DETERMINATION OF TOTAL, TEMPORARY AND
PERMANENT HARDNESS OF WATER

AIM
To estimate the amount of total, temporary & permanent hardness in the given sample of water.

PRINCIPLE
The estimation is based on the complexometric titration.

(i) Total hardness of water is estimated by titrating against EDTA using EBT indicator.
EBT+M ?[EBT-M] (unstable complex)
(EBT-M) (Unstable complex) +EDTA ? [EDTA-M] (stable complex) +EBT
EBT indicator forms wine- red colored complex with metal ions present in water. On addition of EDTA
metal ions preferably forms complexes with EDTA and steel blue EBT indicator is set free. Therefore
change of colour from wine- red to steel blue denotes the end point.

(ii) Temporary hardness is removed by boiling the water.
Ca (HCO 3) 2 ? CaCO 3 +CO 2 ?+H 2O
Mg (HCO 3) 2 ? Mg(OH) 2 +2CO 2 ?
The precipitate is filtered and the remaining permanent hardness is estimated using EDTA.

PROCEDURE

TITRATION ? I
STANDARDISATION OF EDTA

Pipette out 20ml of standard hard water into a 250ml conical flask. Add 5ml of buffer solution and 3
drops of eriochrome black T indictor. Titrate the solution with EDTA from the burette until the colour
changes from wine- red to steel blue at the end point. Repeat the titration for concordant values. Let the
titre value be V 1ml.


16


Titration-II
SAMPLE HARD WATER Vs Std EDTA Indicator: EBT

S.No. Volume of sample
hard water (ml)
Burette Reading Volume of
EDTA
(V 2) (ml)
Concordant value

Initial

Final




CALCULATION

Calculation of total hardness


Volume of EDTA consumed (V 2) = ------------------------- ml
1ml of EDTA = 20 / V 1 mg of CaCO 3
V 2 ml of EDTA = 20 / V 1 x V 2 mg of CaCO 3

( i.e), If 20ml of sample hard water contains 20 x V 2 mg of CaCO 3 / V 1

Then 1000ml of water sample = 20 x V 2 x 1000 / V 1 x 20 mg of CaCO 3

= 1000 x V 2 / V 1 mg of CaCO3

Total hardness of given water sample = ---------------------ppm









17



DETERMINATION OF TOTAL HARDNESS

Pipette out 20ml of sample hard water into a clean conical flask. Add 5ml of buffer solution and 4 -5
drops of Eriochrome black -T indicator. Titrate the wine - red coloured solution with EDTA from the burette until
the colour steel blue appears at the end point. Repeat the titration for concordant values. Let the titre value be
V 2ml.



DETERMINATION OF PERMANENT HARDNESS

Take 100ml of hard water sample in a 500ml beaker and boil gently for about 1hour. Cool, filter it into a
100ml standard flask and make the volume up to the mark. Take 20ml of this solution and proceed it in the same
way as in titration (I). The volume of EDTA consumed corresponds to the permanent hardness of the water
sample. Let the titre value be V 3ml. Temporary hardness is calculated by subtracting permanent hardness from
total hardness.





















18




DETERMINATION OF PERMANENT HARDNESS
BOILED SAMPLE WATER Vs Std. EDTA Indicator: EBT


S.No.
Volume of boiled
hard water (ml)
Burette Reading (ml) Volume of
EDTA
(ml)

Concordant value

Initial Final



CALCULATION OF PERMANENT HARDNESS


Volume of EDTA consumed V 3 = ---------------------ml

1ml of EDTA = 20 / V 1 mg of CaCO 3

V 3ml of EDTA = 20 / V 1 x V 3 mg of CaCO 3

(i.e) 20 ml of boiled sample hard water = 20 / V 1 x V 3 mg of CaCO 3

Then 1000ml of boiled water sample = 20 / V 1 x V 3 / 20 * 1000mg of CaCO 3

= 1000 x V 3 / V 1 mg of CaCO 3

permanent hardness of boiled water sample = -----------------ppm

Temporary hardness of the given water sample = Total hardness ? Permanent hardness

= ------------------ppm

FirstRanker.com - FirstRanker's Choice



?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





3


PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)
1. Fundamentals
To provide students with a solid foundation in Mathematics, Science and fundamentals of engineering,
enabling them to apply, to find solutions for engineering problems and use this knowledge to acquire higher
education
2. Core Competence
To train the students in chemistry practicals so that they apply their knowledge and training to compare,
and to analyze various engineering industrial problems to find solutions
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice this enables
them to find solutions for the real time problems in industry, and to design products
4. Professionalism
To inculcate professional and effective communication skills, leadership qualities and team spirit in the
students to make them multi-faceted personalities and develop their ability to relate engineering issues to
broader social context
5. Lifelong Learning/Ethics
To demonstrate and practice ethical and professional responsibilities in the industry and society in the
large, through commitment and lifelong learning needed for successful professional career






4


PROGRAMME OUTCOMES (POs)
To demonstrate and apply knowledge of Mathematics, Science and engineering fundamentals in the following
experiments.
1 .To estimate HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. To determine total, temporary & permanent hardness of water by EDTA method.
3. To determine DO content of water sample by Winkler?s method.
4. To determine chloride content of water sample by Argentometric method.
5. To estimate copper content of the given solution by Iodometry.
6. To determine strength of given hydrochloric acid using pH meter.
7. To determine strength of acids in a mixture of acids using conductivity meter.
8. To determine iron content of the given solution using potentiometer.
9. To estimate iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. To estimate sodium and potassium present in water using flame photometer.
11. To determine molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. To determine Pseudo first order kinetics ? ester hydrolysis.
13. To determine Corrosion experiment ? weight loss method.
14. To estimate CMC.
15. To estimate Phase change in a solid.
16. To determine strength of strong acid vs strong base using conductivity meter.











5

BS8161 - CHEMISTRY LABORATORY
SYLLABUS


? To make the student to acquire practical skills in the determination of water quality
parameters through volumetric and instrumental analysis.

? ???? ??? ???? ?? ???? ? ? ?To acquaint the students with the determination of molecular weight of a polymer by
viscometery.

LIST OF EXPERIMENTS:
1. Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. Determination of total, temporary & permanent hardness of water by EDTA method.
3. Determination of DO content of water sample by Winkler?s method.
4. Determination of chloride content of water sample by Argentometric method.
5. Estimation of copper content of the given solution by Iodometry.
6. Determination of strength of given hydrochloric acid using pH meter.
7. Determination of strength of acids in a mixture of acids using conductivity meter.
8. Estimation of iron content of the given solution using potentiometer.
9. Estimation of iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. Estimation of sodium and potassium present in water using flame photometer.
11. Determination of molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. Pseudo first order kinetics ? ester hydrolysis.
13. Corrosion experiment ? weight loss method.
14. Determination of CMC.
15. Phase change in a solid.
16. Conductometric titration of strong acid vs strong base.




? The students will be outfitted with hands-on knowledge in the quantitative chemical
analysis of water quality related parameters.
COURSE OBJECTIVES
COURSE OUTCOMES
6


INDEX [ SEMESTER ? I ]


S.No.



Date


Experiment

Date of
submission



Mark


Signature

1.

Estimation of HCl using Na 2CO 3 as
primary standard and Determination of
alkalinity in water sample.



2.


Determination of total, temporary &
permanent hardness of water by EDTA
method.



3.


Determination of chloride content of water
sample by argentometric method.



4.


Determination of strength of given
hydrochloric acid using pH meter.



5.


Determination of strength of acids in a
mixture of acids using conductivity meter.



6.


Estimation of iron content of the given
solution using potentiometer.



7.





Conductometric titration of strong acid Vs
strong base.



8.



Estimation of copper content of the given
solution by Iodometry


9.
Estimation of sodium and potassium
present in water using flame photometer




7




CONTENTS


S.No.


NAME OF EXPERIMENT

PAGE
No.
SEMESTER - I
1.
Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in
water sample.
09
2. Determination of total, temporary & permanent hardness of water by EDTA method. 15
3. Determination of chloride content of water sample by Argentometric method. 21
4. Determination of strength of given hydrochloric acid using pH meter. 25
5. Determination of strength of acids in a mixture of acids using conductivity meter. 29
6. Estimation of iron content of the given solution using potentiometer. 33
7. Conductometric titration of strong acid Vs strong base.

39


42

8


Estimation of copper content of the given solution by Iodometry 43
9 Estimation of sodium and potassium present in water using flame photometer 47






8



SHORT PROCEDURE:

CONTENTS
TITRATION
Estimation of alkalinity in water sample
(Std HCl Vs water sample)

Burette solution

Std. HCl


Pipette solution

Water sample


Indicator


(i) Phenolphthalein
(ii) Methyl orange


End point

(i) Disappearance of pink colour
(ii) Appearance of reddish orange colour






Relationship
between P &M
Nature of alkalinity
Amount of individual
alkalinities
OH
-
HCO 3
-


CO 3
2-

P = M

only OH
-

P or M

?
0.0

0.0


2P = M

only CO 3
2-


2P or M


0.0


0.0


?

P =0, M?0

only HCO 3
-



M



0.0



?

0.0


2P > M


OH
-
&CO 3
2-


OH
-
= 2P-M
CO 3
2-
= 2(M-P)


?

0.0

?

P < ? M




HCO 3
-
&CO 3
2-


HCO 3
-
= M-2P
CO 3
2-
= 2P

0.0 ? ?




9





Expt. No. 1 DETERMINATION OF ALKALINITY IN WATER
AIM
To determine the type and amounts of alkalinity in the given water sample. A standard solution of Na 2CO 3
of strength ____N is given.

PRINCIPLE
Alkalinity in water is due to the presence of soluble hydroxides, bicarbonates and carbonates.
Determination of various types and amounts of alkalinity is easily carried out by titration with standard HCl
employing the indicators phenolphthalein and methyl orange independently or in succession.

The following reactions occur when different types of alkalinity are neutralized with acid.

OH
?
+ H
+
? H 2O completed at pH 8.2-9.0 ----- (1)

CO 3
2 ?
+ H
+
? HCO 3
?
----- (2)

HCO 3
?
+ H
+
? (H 2CO 3) ? H 2O + CO 2, completed at pH 4.2-5.5 ----- (3)

Neutralisation (1) & (2) will be notified by phenolphthalein end-point while all the three will be

accounted by
methyl orange end-point. Bicarbonate in eqn. (3) may be due to the existence of soluble free bicarbonate salts and
bicarbonates resulting from half neutralization of soluble carbonates (eqn. (2))

Various steps to be followed

a) A known volume of water sample is titrated against std. HCl using first phenolphthalein indicator till
end-point (P) and the titration is continued without break using methyl orange indicator till the end-
point (M).



10


Titration

Estimation of Alkalinity in water sample

Standard HCl Vs Water sample Indicator: 1. Phenolphthalein
2. Methyl Orange


S.No.
Volume
of water
sample (ml)
Burette Reading
Concordant value

Initial Phenolphthalein End
Point (P)
Methyl Orange End
Point (M)

1

2






CALCULATION

Hydroxide ion alkalinity
Volume of HCl (2P-M) = ???????ml

Strength of HCl = ???????? N

Volume of water sample = ???????...ml

Strength of water sample = Volume of HCl (2P-M) x Strength of HCl
Volume of water sample

=

? Hydroxide ion alkalinity in terms of
CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ??????.mg/l







11




b) From the magnitudes of the P & M, the nature of alkalinity can be arrived as follows:

(i) P = M => Presence of only OH
-

(ii) 2P = M => Presence of only CO 3
2-

(iii) P =0, M=0 => Presence of only HCO 3
-
(iv) 2P > M => Presence of OH
-
& CO 3
2-
(v) 2P < M => Presence of HCO 3
-
& CO 3
2-

(Mixture of OH
-
& HCO3
-
is not listed since they do not exist together and are considered equivalent to CO 3
2-
).

PROCEDURE
TITRATION
ESTIMATION OF ALKALINITY IN WATER SAMPLE

Exactly 20 ml of water sample is pipetted out into a clean conical flask. Few drops of phenolphthalein
indicator are added and titrated against a standardized HCl taken in the burette. The end point is the
disappearance of pink colour, which is noted as P. Few drops of methyl orange indicator is added to the same
solution. The solution turns to yellow. The titration is continued further by adding same HCl without break till the
end point is reached. The end point is the colour change from yellow to reddish orange.

The experiment is repeated to get concordant values. From the magnitudes of P & M values, the type of
alkalinity present in the water sample is inferred and the individual amounts are calculated and reported.










12


Carbonate ion alkalinity

Volume of HCl 2 (M ? P) = ??? ????????ml

Strength of HCl = ??.?????..???...N

Volume of water sample =........................................ml

Strength of water sample = Volume of HCl 2 (M ? P) x Strength of HCl
Volume of water sample

= ???????????.. N




? Carbonate ion alkalinity
in terms of CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ???????????mg/l

















13





RESULT

1) The type of alkalinity present in the water sample = -------------------------ions.

2) The individual amounts of alkalinity present in the water sample:
Hydroxide ion alkalinity

= ----------------- ppm
Carbonate ion alkalinity = ------------------ ppm
Bicarbonate ion alkalinity = ----------------- ppm





VIVA-VOCE


1. What is meant by alkalinity?
2. What are the ions responsible for alkalinity?
3. Why OH
-
and HCO 3
?
ions cannot exist together in water?
4. What are the ions responsible for alkalinity when 2P > M?
5. What is the pH range for both in acidic and basic solutions?
6. What is the colour of phenolphthalein in an acid and in an alkaline solution?
7. What is the purpose of using two indicators in same titration?
8. What are the possible combinations of ions for alkalinity?
9. How is the amount of alkalinity expressed?
10. What are the types of indicator used in this experiment?







14

SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II TITRATION III
Standardisation of
EDTA
(EDTA Vs Std
Hard water)
Determination of
total hardness
(Std EDTA Vs Hard
water sample)
Determination of
permanent hardness
(Std EDTA Vs Boiled
Hard water sample)

Burette solution

EDTA solution

EDTA solution

EDTA solution

Pipette solution

20ml Std. hard water

20 ml hard water sample

20ml boiled hard water sample

Indicator

2 drops of EBT

2 drops of EBT

2 drops of EBT

Additional soln.


Ammoniacal Buffer
solution (5ml)

Ammoniacal Buffer solution
(5ml)

Ammoniacal Buffer solution
(5ml)
End point Wine - red to Steel blue Wine - red to steel blue Wine - red to Steel blue




STANDARDISATION OF EDTA
Titration - I
Std. HARD WATER Vs EDTA Indicator: EBT

S. No.
Volume of std hard
water (ml)
Burette Reading Volume of
EDTA
(V 1) (ml)
Concordant value

Initial

Final



Volume of std .hard water taken = 20 ml
Volume of EDTA consumed (V 1) = --------------- ml
1 ml of std.hard water = 1mg of CaCO 3
20 ml of std hard water = 20 mg of CaCO 3

V 1 ml of EDTA solution containing 20 mg of CaCO 3
1 ml of EDTA solution = 20 / V 1 mg of CaCO 3
= -----------------------mg of CaCO 3


15

Expt. No. 2 DETERMINATION OF TOTAL, TEMPORARY AND
PERMANENT HARDNESS OF WATER

AIM
To estimate the amount of total, temporary & permanent hardness in the given sample of water.

PRINCIPLE
The estimation is based on the complexometric titration.

(i) Total hardness of water is estimated by titrating against EDTA using EBT indicator.
EBT+M ?[EBT-M] (unstable complex)
(EBT-M) (Unstable complex) +EDTA ? [EDTA-M] (stable complex) +EBT
EBT indicator forms wine- red colored complex with metal ions present in water. On addition of EDTA
metal ions preferably forms complexes with EDTA and steel blue EBT indicator is set free. Therefore
change of colour from wine- red to steel blue denotes the end point.

(ii) Temporary hardness is removed by boiling the water.
Ca (HCO 3) 2 ? CaCO 3 +CO 2 ?+H 2O
Mg (HCO 3) 2 ? Mg(OH) 2 +2CO 2 ?
The precipitate is filtered and the remaining permanent hardness is estimated using EDTA.

PROCEDURE

TITRATION ? I
STANDARDISATION OF EDTA

Pipette out 20ml of standard hard water into a 250ml conical flask. Add 5ml of buffer solution and 3
drops of eriochrome black T indictor. Titrate the solution with EDTA from the burette until the colour
changes from wine- red to steel blue at the end point. Repeat the titration for concordant values. Let the
titre value be V 1ml.


16


Titration-II
SAMPLE HARD WATER Vs Std EDTA Indicator: EBT

S.No. Volume of sample
hard water (ml)
Burette Reading Volume of
EDTA
(V 2) (ml)
Concordant value

Initial

Final




CALCULATION

Calculation of total hardness


Volume of EDTA consumed (V 2) = ------------------------- ml
1ml of EDTA = 20 / V 1 mg of CaCO 3
V 2 ml of EDTA = 20 / V 1 x V 2 mg of CaCO 3

( i.e), If 20ml of sample hard water contains 20 x V 2 mg of CaCO 3 / V 1

Then 1000ml of water sample = 20 x V 2 x 1000 / V 1 x 20 mg of CaCO 3

= 1000 x V 2 / V 1 mg of CaCO3

Total hardness of given water sample = ---------------------ppm









17



DETERMINATION OF TOTAL HARDNESS

Pipette out 20ml of sample hard water into a clean conical flask. Add 5ml of buffer solution and 4 -5
drops of Eriochrome black -T indicator. Titrate the wine - red coloured solution with EDTA from the burette until
the colour steel blue appears at the end point. Repeat the titration for concordant values. Let the titre value be
V 2ml.



DETERMINATION OF PERMANENT HARDNESS

Take 100ml of hard water sample in a 500ml beaker and boil gently for about 1hour. Cool, filter it into a
100ml standard flask and make the volume up to the mark. Take 20ml of this solution and proceed it in the same
way as in titration (I). The volume of EDTA consumed corresponds to the permanent hardness of the water
sample. Let the titre value be V 3ml. Temporary hardness is calculated by subtracting permanent hardness from
total hardness.





















18




DETERMINATION OF PERMANENT HARDNESS
BOILED SAMPLE WATER Vs Std. EDTA Indicator: EBT


S.No.
Volume of boiled
hard water (ml)
Burette Reading (ml) Volume of
EDTA
(ml)

Concordant value

Initial Final



CALCULATION OF PERMANENT HARDNESS


Volume of EDTA consumed V 3 = ---------------------ml

1ml of EDTA = 20 / V 1 mg of CaCO 3

V 3ml of EDTA = 20 / V 1 x V 3 mg of CaCO 3

(i.e) 20 ml of boiled sample hard water = 20 / V 1 x V 3 mg of CaCO 3

Then 1000ml of boiled water sample = 20 / V 1 x V 3 / 20 * 1000mg of CaCO 3

= 1000 x V 3 / V 1 mg of CaCO 3

permanent hardness of boiled water sample = -----------------ppm

Temporary hardness of the given water sample = Total hardness ? Permanent hardness

= ------------------ppm

19







RESULT

(i) Total hardness of the given sample water = -------------- ppm.
(ii) Permanent hardness of the given sample water = --------------- ppm.
(iii) Temporary hardness of the given sample water = ----------------ppm.







VIVA-VOCE

1. Define ? Hard water
2. What is the structure of EDTA?
3. How will you calculate temporary hardness?
4. What is the role of the buffer in EDTA titration?
5. What is the permissible limit of hardness in drinking water?
6. Name the hardness producing ions present in water.
7. Name two salts which are responsible for temporary hardness.
8. Why is CaCO 3 taken as the standard?
9. Write the expansion of EDTA.
10. What is meant by EBT?











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?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





3


PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)
1. Fundamentals
To provide students with a solid foundation in Mathematics, Science and fundamentals of engineering,
enabling them to apply, to find solutions for engineering problems and use this knowledge to acquire higher
education
2. Core Competence
To train the students in chemistry practicals so that they apply their knowledge and training to compare,
and to analyze various engineering industrial problems to find solutions
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice this enables
them to find solutions for the real time problems in industry, and to design products
4. Professionalism
To inculcate professional and effective communication skills, leadership qualities and team spirit in the
students to make them multi-faceted personalities and develop their ability to relate engineering issues to
broader social context
5. Lifelong Learning/Ethics
To demonstrate and practice ethical and professional responsibilities in the industry and society in the
large, through commitment and lifelong learning needed for successful professional career






4


PROGRAMME OUTCOMES (POs)
To demonstrate and apply knowledge of Mathematics, Science and engineering fundamentals in the following
experiments.
1 .To estimate HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. To determine total, temporary & permanent hardness of water by EDTA method.
3. To determine DO content of water sample by Winkler?s method.
4. To determine chloride content of water sample by Argentometric method.
5. To estimate copper content of the given solution by Iodometry.
6. To determine strength of given hydrochloric acid using pH meter.
7. To determine strength of acids in a mixture of acids using conductivity meter.
8. To determine iron content of the given solution using potentiometer.
9. To estimate iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. To estimate sodium and potassium present in water using flame photometer.
11. To determine molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. To determine Pseudo first order kinetics ? ester hydrolysis.
13. To determine Corrosion experiment ? weight loss method.
14. To estimate CMC.
15. To estimate Phase change in a solid.
16. To determine strength of strong acid vs strong base using conductivity meter.











5

BS8161 - CHEMISTRY LABORATORY
SYLLABUS


? To make the student to acquire practical skills in the determination of water quality
parameters through volumetric and instrumental analysis.

? ???? ??? ???? ?? ???? ? ? ?To acquaint the students with the determination of molecular weight of a polymer by
viscometery.

LIST OF EXPERIMENTS:
1. Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. Determination of total, temporary & permanent hardness of water by EDTA method.
3. Determination of DO content of water sample by Winkler?s method.
4. Determination of chloride content of water sample by Argentometric method.
5. Estimation of copper content of the given solution by Iodometry.
6. Determination of strength of given hydrochloric acid using pH meter.
7. Determination of strength of acids in a mixture of acids using conductivity meter.
8. Estimation of iron content of the given solution using potentiometer.
9. Estimation of iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. Estimation of sodium and potassium present in water using flame photometer.
11. Determination of molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. Pseudo first order kinetics ? ester hydrolysis.
13. Corrosion experiment ? weight loss method.
14. Determination of CMC.
15. Phase change in a solid.
16. Conductometric titration of strong acid vs strong base.




? The students will be outfitted with hands-on knowledge in the quantitative chemical
analysis of water quality related parameters.
COURSE OBJECTIVES
COURSE OUTCOMES
6


INDEX [ SEMESTER ? I ]


S.No.



Date


Experiment

Date of
submission



Mark


Signature

1.

Estimation of HCl using Na 2CO 3 as
primary standard and Determination of
alkalinity in water sample.



2.


Determination of total, temporary &
permanent hardness of water by EDTA
method.



3.


Determination of chloride content of water
sample by argentometric method.



4.


Determination of strength of given
hydrochloric acid using pH meter.



5.


Determination of strength of acids in a
mixture of acids using conductivity meter.



6.


Estimation of iron content of the given
solution using potentiometer.



7.





Conductometric titration of strong acid Vs
strong base.



8.



Estimation of copper content of the given
solution by Iodometry


9.
Estimation of sodium and potassium
present in water using flame photometer




7




CONTENTS


S.No.


NAME OF EXPERIMENT

PAGE
No.
SEMESTER - I
1.
Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in
water sample.
09
2. Determination of total, temporary & permanent hardness of water by EDTA method. 15
3. Determination of chloride content of water sample by Argentometric method. 21
4. Determination of strength of given hydrochloric acid using pH meter. 25
5. Determination of strength of acids in a mixture of acids using conductivity meter. 29
6. Estimation of iron content of the given solution using potentiometer. 33
7. Conductometric titration of strong acid Vs strong base.

39


42

8


Estimation of copper content of the given solution by Iodometry 43
9 Estimation of sodium and potassium present in water using flame photometer 47






8



SHORT PROCEDURE:

CONTENTS
TITRATION
Estimation of alkalinity in water sample
(Std HCl Vs water sample)

Burette solution

Std. HCl


Pipette solution

Water sample


Indicator


(i) Phenolphthalein
(ii) Methyl orange


End point

(i) Disappearance of pink colour
(ii) Appearance of reddish orange colour






Relationship
between P &M
Nature of alkalinity
Amount of individual
alkalinities
OH
-
HCO 3
-


CO 3
2-

P = M

only OH
-

P or M

?
0.0

0.0


2P = M

only CO 3
2-


2P or M


0.0


0.0


?

P =0, M?0

only HCO 3
-



M



0.0



?

0.0


2P > M


OH
-
&CO 3
2-


OH
-
= 2P-M
CO 3
2-
= 2(M-P)


?

0.0

?

P < ? M




HCO 3
-
&CO 3
2-


HCO 3
-
= M-2P
CO 3
2-
= 2P

0.0 ? ?




9





Expt. No. 1 DETERMINATION OF ALKALINITY IN WATER
AIM
To determine the type and amounts of alkalinity in the given water sample. A standard solution of Na 2CO 3
of strength ____N is given.

PRINCIPLE
Alkalinity in water is due to the presence of soluble hydroxides, bicarbonates and carbonates.
Determination of various types and amounts of alkalinity is easily carried out by titration with standard HCl
employing the indicators phenolphthalein and methyl orange independently or in succession.

The following reactions occur when different types of alkalinity are neutralized with acid.

OH
?
+ H
+
? H 2O completed at pH 8.2-9.0 ----- (1)

CO 3
2 ?
+ H
+
? HCO 3
?
----- (2)

HCO 3
?
+ H
+
? (H 2CO 3) ? H 2O + CO 2, completed at pH 4.2-5.5 ----- (3)

Neutralisation (1) & (2) will be notified by phenolphthalein end-point while all the three will be

accounted by
methyl orange end-point. Bicarbonate in eqn. (3) may be due to the existence of soluble free bicarbonate salts and
bicarbonates resulting from half neutralization of soluble carbonates (eqn. (2))

Various steps to be followed

a) A known volume of water sample is titrated against std. HCl using first phenolphthalein indicator till
end-point (P) and the titration is continued without break using methyl orange indicator till the end-
point (M).



10


Titration

Estimation of Alkalinity in water sample

Standard HCl Vs Water sample Indicator: 1. Phenolphthalein
2. Methyl Orange


S.No.
Volume
of water
sample (ml)
Burette Reading
Concordant value

Initial Phenolphthalein End
Point (P)
Methyl Orange End
Point (M)

1

2






CALCULATION

Hydroxide ion alkalinity
Volume of HCl (2P-M) = ???????ml

Strength of HCl = ???????? N

Volume of water sample = ???????...ml

Strength of water sample = Volume of HCl (2P-M) x Strength of HCl
Volume of water sample

=

? Hydroxide ion alkalinity in terms of
CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ??????.mg/l







11




b) From the magnitudes of the P & M, the nature of alkalinity can be arrived as follows:

(i) P = M => Presence of only OH
-

(ii) 2P = M => Presence of only CO 3
2-

(iii) P =0, M=0 => Presence of only HCO 3
-
(iv) 2P > M => Presence of OH
-
& CO 3
2-
(v) 2P < M => Presence of HCO 3
-
& CO 3
2-

(Mixture of OH
-
& HCO3
-
is not listed since they do not exist together and are considered equivalent to CO 3
2-
).

PROCEDURE
TITRATION
ESTIMATION OF ALKALINITY IN WATER SAMPLE

Exactly 20 ml of water sample is pipetted out into a clean conical flask. Few drops of phenolphthalein
indicator are added and titrated against a standardized HCl taken in the burette. The end point is the
disappearance of pink colour, which is noted as P. Few drops of methyl orange indicator is added to the same
solution. The solution turns to yellow. The titration is continued further by adding same HCl without break till the
end point is reached. The end point is the colour change from yellow to reddish orange.

The experiment is repeated to get concordant values. From the magnitudes of P & M values, the type of
alkalinity present in the water sample is inferred and the individual amounts are calculated and reported.










12


Carbonate ion alkalinity

Volume of HCl 2 (M ? P) = ??? ????????ml

Strength of HCl = ??.?????..???...N

Volume of water sample =........................................ml

Strength of water sample = Volume of HCl 2 (M ? P) x Strength of HCl
Volume of water sample

= ???????????.. N




? Carbonate ion alkalinity
in terms of CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ???????????mg/l

















13





RESULT

1) The type of alkalinity present in the water sample = -------------------------ions.

2) The individual amounts of alkalinity present in the water sample:
Hydroxide ion alkalinity

= ----------------- ppm
Carbonate ion alkalinity = ------------------ ppm
Bicarbonate ion alkalinity = ----------------- ppm





VIVA-VOCE


1. What is meant by alkalinity?
2. What are the ions responsible for alkalinity?
3. Why OH
-
and HCO 3
?
ions cannot exist together in water?
4. What are the ions responsible for alkalinity when 2P > M?
5. What is the pH range for both in acidic and basic solutions?
6. What is the colour of phenolphthalein in an acid and in an alkaline solution?
7. What is the purpose of using two indicators in same titration?
8. What are the possible combinations of ions for alkalinity?
9. How is the amount of alkalinity expressed?
10. What are the types of indicator used in this experiment?







14

SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II TITRATION III
Standardisation of
EDTA
(EDTA Vs Std
Hard water)
Determination of
total hardness
(Std EDTA Vs Hard
water sample)
Determination of
permanent hardness
(Std EDTA Vs Boiled
Hard water sample)

Burette solution

EDTA solution

EDTA solution

EDTA solution

Pipette solution

20ml Std. hard water

20 ml hard water sample

20ml boiled hard water sample

Indicator

2 drops of EBT

2 drops of EBT

2 drops of EBT

Additional soln.


Ammoniacal Buffer
solution (5ml)

Ammoniacal Buffer solution
(5ml)

Ammoniacal Buffer solution
(5ml)
End point Wine - red to Steel blue Wine - red to steel blue Wine - red to Steel blue




STANDARDISATION OF EDTA
Titration - I
Std. HARD WATER Vs EDTA Indicator: EBT

S. No.
Volume of std hard
water (ml)
Burette Reading Volume of
EDTA
(V 1) (ml)
Concordant value

Initial

Final



Volume of std .hard water taken = 20 ml
Volume of EDTA consumed (V 1) = --------------- ml
1 ml of std.hard water = 1mg of CaCO 3
20 ml of std hard water = 20 mg of CaCO 3

V 1 ml of EDTA solution containing 20 mg of CaCO 3
1 ml of EDTA solution = 20 / V 1 mg of CaCO 3
= -----------------------mg of CaCO 3


15

Expt. No. 2 DETERMINATION OF TOTAL, TEMPORARY AND
PERMANENT HARDNESS OF WATER

AIM
To estimate the amount of total, temporary & permanent hardness in the given sample of water.

PRINCIPLE
The estimation is based on the complexometric titration.

(i) Total hardness of water is estimated by titrating against EDTA using EBT indicator.
EBT+M ?[EBT-M] (unstable complex)
(EBT-M) (Unstable complex) +EDTA ? [EDTA-M] (stable complex) +EBT
EBT indicator forms wine- red colored complex with metal ions present in water. On addition of EDTA
metal ions preferably forms complexes with EDTA and steel blue EBT indicator is set free. Therefore
change of colour from wine- red to steel blue denotes the end point.

(ii) Temporary hardness is removed by boiling the water.
Ca (HCO 3) 2 ? CaCO 3 +CO 2 ?+H 2O
Mg (HCO 3) 2 ? Mg(OH) 2 +2CO 2 ?
The precipitate is filtered and the remaining permanent hardness is estimated using EDTA.

PROCEDURE

TITRATION ? I
STANDARDISATION OF EDTA

Pipette out 20ml of standard hard water into a 250ml conical flask. Add 5ml of buffer solution and 3
drops of eriochrome black T indictor. Titrate the solution with EDTA from the burette until the colour
changes from wine- red to steel blue at the end point. Repeat the titration for concordant values. Let the
titre value be V 1ml.


16


Titration-II
SAMPLE HARD WATER Vs Std EDTA Indicator: EBT

S.No. Volume of sample
hard water (ml)
Burette Reading Volume of
EDTA
(V 2) (ml)
Concordant value

Initial

Final




CALCULATION

Calculation of total hardness


Volume of EDTA consumed (V 2) = ------------------------- ml
1ml of EDTA = 20 / V 1 mg of CaCO 3
V 2 ml of EDTA = 20 / V 1 x V 2 mg of CaCO 3

( i.e), If 20ml of sample hard water contains 20 x V 2 mg of CaCO 3 / V 1

Then 1000ml of water sample = 20 x V 2 x 1000 / V 1 x 20 mg of CaCO 3

= 1000 x V 2 / V 1 mg of CaCO3

Total hardness of given water sample = ---------------------ppm









17



DETERMINATION OF TOTAL HARDNESS

Pipette out 20ml of sample hard water into a clean conical flask. Add 5ml of buffer solution and 4 -5
drops of Eriochrome black -T indicator. Titrate the wine - red coloured solution with EDTA from the burette until
the colour steel blue appears at the end point. Repeat the titration for concordant values. Let the titre value be
V 2ml.



DETERMINATION OF PERMANENT HARDNESS

Take 100ml of hard water sample in a 500ml beaker and boil gently for about 1hour. Cool, filter it into a
100ml standard flask and make the volume up to the mark. Take 20ml of this solution and proceed it in the same
way as in titration (I). The volume of EDTA consumed corresponds to the permanent hardness of the water
sample. Let the titre value be V 3ml. Temporary hardness is calculated by subtracting permanent hardness from
total hardness.





















18




DETERMINATION OF PERMANENT HARDNESS
BOILED SAMPLE WATER Vs Std. EDTA Indicator: EBT


S.No.
Volume of boiled
hard water (ml)
Burette Reading (ml) Volume of
EDTA
(ml)

Concordant value

Initial Final



CALCULATION OF PERMANENT HARDNESS


Volume of EDTA consumed V 3 = ---------------------ml

1ml of EDTA = 20 / V 1 mg of CaCO 3

V 3ml of EDTA = 20 / V 1 x V 3 mg of CaCO 3

(i.e) 20 ml of boiled sample hard water = 20 / V 1 x V 3 mg of CaCO 3

Then 1000ml of boiled water sample = 20 / V 1 x V 3 / 20 * 1000mg of CaCO 3

= 1000 x V 3 / V 1 mg of CaCO 3

permanent hardness of boiled water sample = -----------------ppm

Temporary hardness of the given water sample = Total hardness ? Permanent hardness

= ------------------ppm

19







RESULT

(i) Total hardness of the given sample water = -------------- ppm.
(ii) Permanent hardness of the given sample water = --------------- ppm.
(iii) Temporary hardness of the given sample water = ----------------ppm.







VIVA-VOCE

1. Define ? Hard water
2. What is the structure of EDTA?
3. How will you calculate temporary hardness?
4. What is the role of the buffer in EDTA titration?
5. What is the permissible limit of hardness in drinking water?
6. Name the hardness producing ions present in water.
7. Name two salts which are responsible for temporary hardness.
8. Why is CaCO 3 taken as the standard?
9. Write the expansion of EDTA.
10. What is meant by EBT?











20





SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II
Standardisation of
AgNO 3
Estimation of Chloride
Burette solution

AgNO 3 solution

Std. AgNO 3 solution

Pipette solution

20ml std KCl solution

20 ml water sample

Indicator

1ml K 2CrO 4

1ml K 2CrO 4


End point

yellow to reddish brown

yellow to reddish brown

Titration I
Std. AgNO3 Vs KCl Indicator: Potassium Chromate













CALCULATION

Volume of KCl (V 1) = ------- ml

Strength of KCl (N 1) = ------- N

Volume of Silver Nitrate (V 2) = -------- ml

Strength of Siver Nitrate V 1N 1
N 2 =
V 1

= --------------------- N

S.No.
Volume of KCl
(ml)
Burette Reading (ml)
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

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?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





3


PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)
1. Fundamentals
To provide students with a solid foundation in Mathematics, Science and fundamentals of engineering,
enabling them to apply, to find solutions for engineering problems and use this knowledge to acquire higher
education
2. Core Competence
To train the students in chemistry practicals so that they apply their knowledge and training to compare,
and to analyze various engineering industrial problems to find solutions
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice this enables
them to find solutions for the real time problems in industry, and to design products
4. Professionalism
To inculcate professional and effective communication skills, leadership qualities and team spirit in the
students to make them multi-faceted personalities and develop their ability to relate engineering issues to
broader social context
5. Lifelong Learning/Ethics
To demonstrate and practice ethical and professional responsibilities in the industry and society in the
large, through commitment and lifelong learning needed for successful professional career






4


PROGRAMME OUTCOMES (POs)
To demonstrate and apply knowledge of Mathematics, Science and engineering fundamentals in the following
experiments.
1 .To estimate HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. To determine total, temporary & permanent hardness of water by EDTA method.
3. To determine DO content of water sample by Winkler?s method.
4. To determine chloride content of water sample by Argentometric method.
5. To estimate copper content of the given solution by Iodometry.
6. To determine strength of given hydrochloric acid using pH meter.
7. To determine strength of acids in a mixture of acids using conductivity meter.
8. To determine iron content of the given solution using potentiometer.
9. To estimate iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. To estimate sodium and potassium present in water using flame photometer.
11. To determine molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. To determine Pseudo first order kinetics ? ester hydrolysis.
13. To determine Corrosion experiment ? weight loss method.
14. To estimate CMC.
15. To estimate Phase change in a solid.
16. To determine strength of strong acid vs strong base using conductivity meter.











5

BS8161 - CHEMISTRY LABORATORY
SYLLABUS


? To make the student to acquire practical skills in the determination of water quality
parameters through volumetric and instrumental analysis.

? ???? ??? ???? ?? ???? ? ? ?To acquaint the students with the determination of molecular weight of a polymer by
viscometery.

LIST OF EXPERIMENTS:
1. Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. Determination of total, temporary & permanent hardness of water by EDTA method.
3. Determination of DO content of water sample by Winkler?s method.
4. Determination of chloride content of water sample by Argentometric method.
5. Estimation of copper content of the given solution by Iodometry.
6. Determination of strength of given hydrochloric acid using pH meter.
7. Determination of strength of acids in a mixture of acids using conductivity meter.
8. Estimation of iron content of the given solution using potentiometer.
9. Estimation of iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. Estimation of sodium and potassium present in water using flame photometer.
11. Determination of molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. Pseudo first order kinetics ? ester hydrolysis.
13. Corrosion experiment ? weight loss method.
14. Determination of CMC.
15. Phase change in a solid.
16. Conductometric titration of strong acid vs strong base.




? The students will be outfitted with hands-on knowledge in the quantitative chemical
analysis of water quality related parameters.
COURSE OBJECTIVES
COURSE OUTCOMES
6


INDEX [ SEMESTER ? I ]


S.No.



Date


Experiment

Date of
submission



Mark


Signature

1.

Estimation of HCl using Na 2CO 3 as
primary standard and Determination of
alkalinity in water sample.



2.


Determination of total, temporary &
permanent hardness of water by EDTA
method.



3.


Determination of chloride content of water
sample by argentometric method.



4.


Determination of strength of given
hydrochloric acid using pH meter.



5.


Determination of strength of acids in a
mixture of acids using conductivity meter.



6.


Estimation of iron content of the given
solution using potentiometer.



7.





Conductometric titration of strong acid Vs
strong base.



8.



Estimation of copper content of the given
solution by Iodometry


9.
Estimation of sodium and potassium
present in water using flame photometer




7




CONTENTS


S.No.


NAME OF EXPERIMENT

PAGE
No.
SEMESTER - I
1.
Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in
water sample.
09
2. Determination of total, temporary & permanent hardness of water by EDTA method. 15
3. Determination of chloride content of water sample by Argentometric method. 21
4. Determination of strength of given hydrochloric acid using pH meter. 25
5. Determination of strength of acids in a mixture of acids using conductivity meter. 29
6. Estimation of iron content of the given solution using potentiometer. 33
7. Conductometric titration of strong acid Vs strong base.

39


42

8


Estimation of copper content of the given solution by Iodometry 43
9 Estimation of sodium and potassium present in water using flame photometer 47






8



SHORT PROCEDURE:

CONTENTS
TITRATION
Estimation of alkalinity in water sample
(Std HCl Vs water sample)

Burette solution

Std. HCl


Pipette solution

Water sample


Indicator


(i) Phenolphthalein
(ii) Methyl orange


End point

(i) Disappearance of pink colour
(ii) Appearance of reddish orange colour






Relationship
between P &M
Nature of alkalinity
Amount of individual
alkalinities
OH
-
HCO 3
-


CO 3
2-

P = M

only OH
-

P or M

?
0.0

0.0


2P = M

only CO 3
2-


2P or M


0.0


0.0


?

P =0, M?0

only HCO 3
-



M



0.0



?

0.0


2P > M


OH
-
&CO 3
2-


OH
-
= 2P-M
CO 3
2-
= 2(M-P)


?

0.0

?

P < ? M




HCO 3
-
&CO 3
2-


HCO 3
-
= M-2P
CO 3
2-
= 2P

0.0 ? ?




9





Expt. No. 1 DETERMINATION OF ALKALINITY IN WATER
AIM
To determine the type and amounts of alkalinity in the given water sample. A standard solution of Na 2CO 3
of strength ____N is given.

PRINCIPLE
Alkalinity in water is due to the presence of soluble hydroxides, bicarbonates and carbonates.
Determination of various types and amounts of alkalinity is easily carried out by titration with standard HCl
employing the indicators phenolphthalein and methyl orange independently or in succession.

The following reactions occur when different types of alkalinity are neutralized with acid.

OH
?
+ H
+
? H 2O completed at pH 8.2-9.0 ----- (1)

CO 3
2 ?
+ H
+
? HCO 3
?
----- (2)

HCO 3
?
+ H
+
? (H 2CO 3) ? H 2O + CO 2, completed at pH 4.2-5.5 ----- (3)

Neutralisation (1) & (2) will be notified by phenolphthalein end-point while all the three will be

accounted by
methyl orange end-point. Bicarbonate in eqn. (3) may be due to the existence of soluble free bicarbonate salts and
bicarbonates resulting from half neutralization of soluble carbonates (eqn. (2))

Various steps to be followed

a) A known volume of water sample is titrated against std. HCl using first phenolphthalein indicator till
end-point (P) and the titration is continued without break using methyl orange indicator till the end-
point (M).



10


Titration

Estimation of Alkalinity in water sample

Standard HCl Vs Water sample Indicator: 1. Phenolphthalein
2. Methyl Orange


S.No.
Volume
of water
sample (ml)
Burette Reading
Concordant value

Initial Phenolphthalein End
Point (P)
Methyl Orange End
Point (M)

1

2






CALCULATION

Hydroxide ion alkalinity
Volume of HCl (2P-M) = ???????ml

Strength of HCl = ???????? N

Volume of water sample = ???????...ml

Strength of water sample = Volume of HCl (2P-M) x Strength of HCl
Volume of water sample

=

? Hydroxide ion alkalinity in terms of
CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ??????.mg/l







11




b) From the magnitudes of the P & M, the nature of alkalinity can be arrived as follows:

(i) P = M => Presence of only OH
-

(ii) 2P = M => Presence of only CO 3
2-

(iii) P =0, M=0 => Presence of only HCO 3
-
(iv) 2P > M => Presence of OH
-
& CO 3
2-
(v) 2P < M => Presence of HCO 3
-
& CO 3
2-

(Mixture of OH
-
& HCO3
-
is not listed since they do not exist together and are considered equivalent to CO 3
2-
).

PROCEDURE
TITRATION
ESTIMATION OF ALKALINITY IN WATER SAMPLE

Exactly 20 ml of water sample is pipetted out into a clean conical flask. Few drops of phenolphthalein
indicator are added and titrated against a standardized HCl taken in the burette. The end point is the
disappearance of pink colour, which is noted as P. Few drops of methyl orange indicator is added to the same
solution. The solution turns to yellow. The titration is continued further by adding same HCl without break till the
end point is reached. The end point is the colour change from yellow to reddish orange.

The experiment is repeated to get concordant values. From the magnitudes of P & M values, the type of
alkalinity present in the water sample is inferred and the individual amounts are calculated and reported.










12


Carbonate ion alkalinity

Volume of HCl 2 (M ? P) = ??? ????????ml

Strength of HCl = ??.?????..???...N

Volume of water sample =........................................ml

Strength of water sample = Volume of HCl 2 (M ? P) x Strength of HCl
Volume of water sample

= ???????????.. N




? Carbonate ion alkalinity
in terms of CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ???????????mg/l

















13





RESULT

1) The type of alkalinity present in the water sample = -------------------------ions.

2) The individual amounts of alkalinity present in the water sample:
Hydroxide ion alkalinity

= ----------------- ppm
Carbonate ion alkalinity = ------------------ ppm
Bicarbonate ion alkalinity = ----------------- ppm





VIVA-VOCE


1. What is meant by alkalinity?
2. What are the ions responsible for alkalinity?
3. Why OH
-
and HCO 3
?
ions cannot exist together in water?
4. What are the ions responsible for alkalinity when 2P > M?
5. What is the pH range for both in acidic and basic solutions?
6. What is the colour of phenolphthalein in an acid and in an alkaline solution?
7. What is the purpose of using two indicators in same titration?
8. What are the possible combinations of ions for alkalinity?
9. How is the amount of alkalinity expressed?
10. What are the types of indicator used in this experiment?







14

SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II TITRATION III
Standardisation of
EDTA
(EDTA Vs Std
Hard water)
Determination of
total hardness
(Std EDTA Vs Hard
water sample)
Determination of
permanent hardness
(Std EDTA Vs Boiled
Hard water sample)

Burette solution

EDTA solution

EDTA solution

EDTA solution

Pipette solution

20ml Std. hard water

20 ml hard water sample

20ml boiled hard water sample

Indicator

2 drops of EBT

2 drops of EBT

2 drops of EBT

Additional soln.


Ammoniacal Buffer
solution (5ml)

Ammoniacal Buffer solution
(5ml)

Ammoniacal Buffer solution
(5ml)
End point Wine - red to Steel blue Wine - red to steel blue Wine - red to Steel blue




STANDARDISATION OF EDTA
Titration - I
Std. HARD WATER Vs EDTA Indicator: EBT

S. No.
Volume of std hard
water (ml)
Burette Reading Volume of
EDTA
(V 1) (ml)
Concordant value

Initial

Final



Volume of std .hard water taken = 20 ml
Volume of EDTA consumed (V 1) = --------------- ml
1 ml of std.hard water = 1mg of CaCO 3
20 ml of std hard water = 20 mg of CaCO 3

V 1 ml of EDTA solution containing 20 mg of CaCO 3
1 ml of EDTA solution = 20 / V 1 mg of CaCO 3
= -----------------------mg of CaCO 3


15

Expt. No. 2 DETERMINATION OF TOTAL, TEMPORARY AND
PERMANENT HARDNESS OF WATER

AIM
To estimate the amount of total, temporary & permanent hardness in the given sample of water.

PRINCIPLE
The estimation is based on the complexometric titration.

(i) Total hardness of water is estimated by titrating against EDTA using EBT indicator.
EBT+M ?[EBT-M] (unstable complex)
(EBT-M) (Unstable complex) +EDTA ? [EDTA-M] (stable complex) +EBT
EBT indicator forms wine- red colored complex with metal ions present in water. On addition of EDTA
metal ions preferably forms complexes with EDTA and steel blue EBT indicator is set free. Therefore
change of colour from wine- red to steel blue denotes the end point.

(ii) Temporary hardness is removed by boiling the water.
Ca (HCO 3) 2 ? CaCO 3 +CO 2 ?+H 2O
Mg (HCO 3) 2 ? Mg(OH) 2 +2CO 2 ?
The precipitate is filtered and the remaining permanent hardness is estimated using EDTA.

PROCEDURE

TITRATION ? I
STANDARDISATION OF EDTA

Pipette out 20ml of standard hard water into a 250ml conical flask. Add 5ml of buffer solution and 3
drops of eriochrome black T indictor. Titrate the solution with EDTA from the burette until the colour
changes from wine- red to steel blue at the end point. Repeat the titration for concordant values. Let the
titre value be V 1ml.


16


Titration-II
SAMPLE HARD WATER Vs Std EDTA Indicator: EBT

S.No. Volume of sample
hard water (ml)
Burette Reading Volume of
EDTA
(V 2) (ml)
Concordant value

Initial

Final




CALCULATION

Calculation of total hardness


Volume of EDTA consumed (V 2) = ------------------------- ml
1ml of EDTA = 20 / V 1 mg of CaCO 3
V 2 ml of EDTA = 20 / V 1 x V 2 mg of CaCO 3

( i.e), If 20ml of sample hard water contains 20 x V 2 mg of CaCO 3 / V 1

Then 1000ml of water sample = 20 x V 2 x 1000 / V 1 x 20 mg of CaCO 3

= 1000 x V 2 / V 1 mg of CaCO3

Total hardness of given water sample = ---------------------ppm









17



DETERMINATION OF TOTAL HARDNESS

Pipette out 20ml of sample hard water into a clean conical flask. Add 5ml of buffer solution and 4 -5
drops of Eriochrome black -T indicator. Titrate the wine - red coloured solution with EDTA from the burette until
the colour steel blue appears at the end point. Repeat the titration for concordant values. Let the titre value be
V 2ml.



DETERMINATION OF PERMANENT HARDNESS

Take 100ml of hard water sample in a 500ml beaker and boil gently for about 1hour. Cool, filter it into a
100ml standard flask and make the volume up to the mark. Take 20ml of this solution and proceed it in the same
way as in titration (I). The volume of EDTA consumed corresponds to the permanent hardness of the water
sample. Let the titre value be V 3ml. Temporary hardness is calculated by subtracting permanent hardness from
total hardness.





















18




DETERMINATION OF PERMANENT HARDNESS
BOILED SAMPLE WATER Vs Std. EDTA Indicator: EBT


S.No.
Volume of boiled
hard water (ml)
Burette Reading (ml) Volume of
EDTA
(ml)

Concordant value

Initial Final



CALCULATION OF PERMANENT HARDNESS


Volume of EDTA consumed V 3 = ---------------------ml

1ml of EDTA = 20 / V 1 mg of CaCO 3

V 3ml of EDTA = 20 / V 1 x V 3 mg of CaCO 3

(i.e) 20 ml of boiled sample hard water = 20 / V 1 x V 3 mg of CaCO 3

Then 1000ml of boiled water sample = 20 / V 1 x V 3 / 20 * 1000mg of CaCO 3

= 1000 x V 3 / V 1 mg of CaCO 3

permanent hardness of boiled water sample = -----------------ppm

Temporary hardness of the given water sample = Total hardness ? Permanent hardness

= ------------------ppm

19







RESULT

(i) Total hardness of the given sample water = -------------- ppm.
(ii) Permanent hardness of the given sample water = --------------- ppm.
(iii) Temporary hardness of the given sample water = ----------------ppm.







VIVA-VOCE

1. Define ? Hard water
2. What is the structure of EDTA?
3. How will you calculate temporary hardness?
4. What is the role of the buffer in EDTA titration?
5. What is the permissible limit of hardness in drinking water?
6. Name the hardness producing ions present in water.
7. Name two salts which are responsible for temporary hardness.
8. Why is CaCO 3 taken as the standard?
9. Write the expansion of EDTA.
10. What is meant by EBT?











20





SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II
Standardisation of
AgNO 3
Estimation of Chloride
Burette solution

AgNO 3 solution

Std. AgNO 3 solution

Pipette solution

20ml std KCl solution

20 ml water sample

Indicator

1ml K 2CrO 4

1ml K 2CrO 4


End point

yellow to reddish brown

yellow to reddish brown

Titration I
Std. AgNO3 Vs KCl Indicator: Potassium Chromate













CALCULATION

Volume of KCl (V 1) = ------- ml

Strength of KCl (N 1) = ------- N

Volume of Silver Nitrate (V 2) = -------- ml

Strength of Siver Nitrate V 1N 1
N 2 =
V 1

= --------------------- N

S.No.
Volume of KCl
(ml)
Burette Reading (ml)
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

21




Expt.No. 3 ESTIMATION OF CHLORIDE CONTENT IN WATER
(ARGENTOMETRIC METHOD)
AIM
To estimate the amount of chloride present in given water sample by Argentometric method (Mohr?s
method). You are provided with standard solution of NaCl of strength --------N and a approximately N/10 solution of
Silver nitrate.

PRINCIPLE
The Chloride ion in the form of NaCl, KCl, CaCl 2, MgCl 2 etc., present in the water sample can be estimated
by Argentometric method or known as Mohr?s method. It is an example for precipitation titration. The reaction
between std. Sodium chloride and Silver nitrate is given below.
AgNO 3 + NaCl ? AgCl ? + NaNO 3
The completion of reaction can be observed by employing potassium chromate as the indicator. The end
point is the colour change from yellow to reddish brown due to the following reaction.
2AgNO 3 + K 2CrO 4 ? Ag 2CrO 4 ? + 2KNO 3
Potassium chromate indicator will not be precipitated as silver chromate until all the chlorides in the solution
have been precipitated as AgCl Since a precipitation reaction takes place in preference, this reaction takes place
only at the end point.

PROCEDURE
TITRATION I: STANDARDISATION OF SILVER NITRATE
Pipette out 20ml of standard sodium or potassium chloride solution into a clean conical flask. Add 1ml of 5%
K 2CrO 4 indicator, as the solution turns yellow in colour. Titrate it against silver nitrate solution taken in the burette.
Observe the nearness of the end point through the formation of coagulated silver chloride precipitate at the bottom
of the flask. Now add the silver nitrate drop by drop until the solution gets a faint reddish brown tinge. Repeat the
titration for concordant value. Let the volume of silver nitrate be V 2ml.





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?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





3


PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)
1. Fundamentals
To provide students with a solid foundation in Mathematics, Science and fundamentals of engineering,
enabling them to apply, to find solutions for engineering problems and use this knowledge to acquire higher
education
2. Core Competence
To train the students in chemistry practicals so that they apply their knowledge and training to compare,
and to analyze various engineering industrial problems to find solutions
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice this enables
them to find solutions for the real time problems in industry, and to design products
4. Professionalism
To inculcate professional and effective communication skills, leadership qualities and team spirit in the
students to make them multi-faceted personalities and develop their ability to relate engineering issues to
broader social context
5. Lifelong Learning/Ethics
To demonstrate and practice ethical and professional responsibilities in the industry and society in the
large, through commitment and lifelong learning needed for successful professional career






4


PROGRAMME OUTCOMES (POs)
To demonstrate and apply knowledge of Mathematics, Science and engineering fundamentals in the following
experiments.
1 .To estimate HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. To determine total, temporary & permanent hardness of water by EDTA method.
3. To determine DO content of water sample by Winkler?s method.
4. To determine chloride content of water sample by Argentometric method.
5. To estimate copper content of the given solution by Iodometry.
6. To determine strength of given hydrochloric acid using pH meter.
7. To determine strength of acids in a mixture of acids using conductivity meter.
8. To determine iron content of the given solution using potentiometer.
9. To estimate iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. To estimate sodium and potassium present in water using flame photometer.
11. To determine molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. To determine Pseudo first order kinetics ? ester hydrolysis.
13. To determine Corrosion experiment ? weight loss method.
14. To estimate CMC.
15. To estimate Phase change in a solid.
16. To determine strength of strong acid vs strong base using conductivity meter.











5

BS8161 - CHEMISTRY LABORATORY
SYLLABUS


? To make the student to acquire practical skills in the determination of water quality
parameters through volumetric and instrumental analysis.

? ???? ??? ???? ?? ???? ? ? ?To acquaint the students with the determination of molecular weight of a polymer by
viscometery.

LIST OF EXPERIMENTS:
1. Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. Determination of total, temporary & permanent hardness of water by EDTA method.
3. Determination of DO content of water sample by Winkler?s method.
4. Determination of chloride content of water sample by Argentometric method.
5. Estimation of copper content of the given solution by Iodometry.
6. Determination of strength of given hydrochloric acid using pH meter.
7. Determination of strength of acids in a mixture of acids using conductivity meter.
8. Estimation of iron content of the given solution using potentiometer.
9. Estimation of iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. Estimation of sodium and potassium present in water using flame photometer.
11. Determination of molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. Pseudo first order kinetics ? ester hydrolysis.
13. Corrosion experiment ? weight loss method.
14. Determination of CMC.
15. Phase change in a solid.
16. Conductometric titration of strong acid vs strong base.




? The students will be outfitted with hands-on knowledge in the quantitative chemical
analysis of water quality related parameters.
COURSE OBJECTIVES
COURSE OUTCOMES
6


INDEX [ SEMESTER ? I ]


S.No.



Date


Experiment

Date of
submission



Mark


Signature

1.

Estimation of HCl using Na 2CO 3 as
primary standard and Determination of
alkalinity in water sample.



2.


Determination of total, temporary &
permanent hardness of water by EDTA
method.



3.


Determination of chloride content of water
sample by argentometric method.



4.


Determination of strength of given
hydrochloric acid using pH meter.



5.


Determination of strength of acids in a
mixture of acids using conductivity meter.



6.


Estimation of iron content of the given
solution using potentiometer.



7.





Conductometric titration of strong acid Vs
strong base.



8.



Estimation of copper content of the given
solution by Iodometry


9.
Estimation of sodium and potassium
present in water using flame photometer




7




CONTENTS


S.No.


NAME OF EXPERIMENT

PAGE
No.
SEMESTER - I
1.
Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in
water sample.
09
2. Determination of total, temporary & permanent hardness of water by EDTA method. 15
3. Determination of chloride content of water sample by Argentometric method. 21
4. Determination of strength of given hydrochloric acid using pH meter. 25
5. Determination of strength of acids in a mixture of acids using conductivity meter. 29
6. Estimation of iron content of the given solution using potentiometer. 33
7. Conductometric titration of strong acid Vs strong base.

39


42

8


Estimation of copper content of the given solution by Iodometry 43
9 Estimation of sodium and potassium present in water using flame photometer 47






8



SHORT PROCEDURE:

CONTENTS
TITRATION
Estimation of alkalinity in water sample
(Std HCl Vs water sample)

Burette solution

Std. HCl


Pipette solution

Water sample


Indicator


(i) Phenolphthalein
(ii) Methyl orange


End point

(i) Disappearance of pink colour
(ii) Appearance of reddish orange colour






Relationship
between P &M
Nature of alkalinity
Amount of individual
alkalinities
OH
-
HCO 3
-


CO 3
2-

P = M

only OH
-

P or M

?
0.0

0.0


2P = M

only CO 3
2-


2P or M


0.0


0.0


?

P =0, M?0

only HCO 3
-



M



0.0



?

0.0


2P > M


OH
-
&CO 3
2-


OH
-
= 2P-M
CO 3
2-
= 2(M-P)


?

0.0

?

P < ? M




HCO 3
-
&CO 3
2-


HCO 3
-
= M-2P
CO 3
2-
= 2P

0.0 ? ?




9





Expt. No. 1 DETERMINATION OF ALKALINITY IN WATER
AIM
To determine the type and amounts of alkalinity in the given water sample. A standard solution of Na 2CO 3
of strength ____N is given.

PRINCIPLE
Alkalinity in water is due to the presence of soluble hydroxides, bicarbonates and carbonates.
Determination of various types and amounts of alkalinity is easily carried out by titration with standard HCl
employing the indicators phenolphthalein and methyl orange independently or in succession.

The following reactions occur when different types of alkalinity are neutralized with acid.

OH
?
+ H
+
? H 2O completed at pH 8.2-9.0 ----- (1)

CO 3
2 ?
+ H
+
? HCO 3
?
----- (2)

HCO 3
?
+ H
+
? (H 2CO 3) ? H 2O + CO 2, completed at pH 4.2-5.5 ----- (3)

Neutralisation (1) & (2) will be notified by phenolphthalein end-point while all the three will be

accounted by
methyl orange end-point. Bicarbonate in eqn. (3) may be due to the existence of soluble free bicarbonate salts and
bicarbonates resulting from half neutralization of soluble carbonates (eqn. (2))

Various steps to be followed

a) A known volume of water sample is titrated against std. HCl using first phenolphthalein indicator till
end-point (P) and the titration is continued without break using methyl orange indicator till the end-
point (M).



10


Titration

Estimation of Alkalinity in water sample

Standard HCl Vs Water sample Indicator: 1. Phenolphthalein
2. Methyl Orange


S.No.
Volume
of water
sample (ml)
Burette Reading
Concordant value

Initial Phenolphthalein End
Point (P)
Methyl Orange End
Point (M)

1

2






CALCULATION

Hydroxide ion alkalinity
Volume of HCl (2P-M) = ???????ml

Strength of HCl = ???????? N

Volume of water sample = ???????...ml

Strength of water sample = Volume of HCl (2P-M) x Strength of HCl
Volume of water sample

=

? Hydroxide ion alkalinity in terms of
CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ??????.mg/l







11




b) From the magnitudes of the P & M, the nature of alkalinity can be arrived as follows:

(i) P = M => Presence of only OH
-

(ii) 2P = M => Presence of only CO 3
2-

(iii) P =0, M=0 => Presence of only HCO 3
-
(iv) 2P > M => Presence of OH
-
& CO 3
2-
(v) 2P < M => Presence of HCO 3
-
& CO 3
2-

(Mixture of OH
-
& HCO3
-
is not listed since they do not exist together and are considered equivalent to CO 3
2-
).

PROCEDURE
TITRATION
ESTIMATION OF ALKALINITY IN WATER SAMPLE

Exactly 20 ml of water sample is pipetted out into a clean conical flask. Few drops of phenolphthalein
indicator are added and titrated against a standardized HCl taken in the burette. The end point is the
disappearance of pink colour, which is noted as P. Few drops of methyl orange indicator is added to the same
solution. The solution turns to yellow. The titration is continued further by adding same HCl without break till the
end point is reached. The end point is the colour change from yellow to reddish orange.

The experiment is repeated to get concordant values. From the magnitudes of P & M values, the type of
alkalinity present in the water sample is inferred and the individual amounts are calculated and reported.










12


Carbonate ion alkalinity

Volume of HCl 2 (M ? P) = ??? ????????ml

Strength of HCl = ??.?????..???...N

Volume of water sample =........................................ml

Strength of water sample = Volume of HCl 2 (M ? P) x Strength of HCl
Volume of water sample

= ???????????.. N




? Carbonate ion alkalinity
in terms of CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ???????????mg/l

















13





RESULT

1) The type of alkalinity present in the water sample = -------------------------ions.

2) The individual amounts of alkalinity present in the water sample:
Hydroxide ion alkalinity

= ----------------- ppm
Carbonate ion alkalinity = ------------------ ppm
Bicarbonate ion alkalinity = ----------------- ppm





VIVA-VOCE


1. What is meant by alkalinity?
2. What are the ions responsible for alkalinity?
3. Why OH
-
and HCO 3
?
ions cannot exist together in water?
4. What are the ions responsible for alkalinity when 2P > M?
5. What is the pH range for both in acidic and basic solutions?
6. What is the colour of phenolphthalein in an acid and in an alkaline solution?
7. What is the purpose of using two indicators in same titration?
8. What are the possible combinations of ions for alkalinity?
9. How is the amount of alkalinity expressed?
10. What are the types of indicator used in this experiment?







14

SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II TITRATION III
Standardisation of
EDTA
(EDTA Vs Std
Hard water)
Determination of
total hardness
(Std EDTA Vs Hard
water sample)
Determination of
permanent hardness
(Std EDTA Vs Boiled
Hard water sample)

Burette solution

EDTA solution

EDTA solution

EDTA solution

Pipette solution

20ml Std. hard water

20 ml hard water sample

20ml boiled hard water sample

Indicator

2 drops of EBT

2 drops of EBT

2 drops of EBT

Additional soln.


Ammoniacal Buffer
solution (5ml)

Ammoniacal Buffer solution
(5ml)

Ammoniacal Buffer solution
(5ml)
End point Wine - red to Steel blue Wine - red to steel blue Wine - red to Steel blue




STANDARDISATION OF EDTA
Titration - I
Std. HARD WATER Vs EDTA Indicator: EBT

S. No.
Volume of std hard
water (ml)
Burette Reading Volume of
EDTA
(V 1) (ml)
Concordant value

Initial

Final



Volume of std .hard water taken = 20 ml
Volume of EDTA consumed (V 1) = --------------- ml
1 ml of std.hard water = 1mg of CaCO 3
20 ml of std hard water = 20 mg of CaCO 3

V 1 ml of EDTA solution containing 20 mg of CaCO 3
1 ml of EDTA solution = 20 / V 1 mg of CaCO 3
= -----------------------mg of CaCO 3


15

Expt. No. 2 DETERMINATION OF TOTAL, TEMPORARY AND
PERMANENT HARDNESS OF WATER

AIM
To estimate the amount of total, temporary & permanent hardness in the given sample of water.

PRINCIPLE
The estimation is based on the complexometric titration.

(i) Total hardness of water is estimated by titrating against EDTA using EBT indicator.
EBT+M ?[EBT-M] (unstable complex)
(EBT-M) (Unstable complex) +EDTA ? [EDTA-M] (stable complex) +EBT
EBT indicator forms wine- red colored complex with metal ions present in water. On addition of EDTA
metal ions preferably forms complexes with EDTA and steel blue EBT indicator is set free. Therefore
change of colour from wine- red to steel blue denotes the end point.

(ii) Temporary hardness is removed by boiling the water.
Ca (HCO 3) 2 ? CaCO 3 +CO 2 ?+H 2O
Mg (HCO 3) 2 ? Mg(OH) 2 +2CO 2 ?
The precipitate is filtered and the remaining permanent hardness is estimated using EDTA.

PROCEDURE

TITRATION ? I
STANDARDISATION OF EDTA

Pipette out 20ml of standard hard water into a 250ml conical flask. Add 5ml of buffer solution and 3
drops of eriochrome black T indictor. Titrate the solution with EDTA from the burette until the colour
changes from wine- red to steel blue at the end point. Repeat the titration for concordant values. Let the
titre value be V 1ml.


16


Titration-II
SAMPLE HARD WATER Vs Std EDTA Indicator: EBT

S.No. Volume of sample
hard water (ml)
Burette Reading Volume of
EDTA
(V 2) (ml)
Concordant value

Initial

Final




CALCULATION

Calculation of total hardness


Volume of EDTA consumed (V 2) = ------------------------- ml
1ml of EDTA = 20 / V 1 mg of CaCO 3
V 2 ml of EDTA = 20 / V 1 x V 2 mg of CaCO 3

( i.e), If 20ml of sample hard water contains 20 x V 2 mg of CaCO 3 / V 1

Then 1000ml of water sample = 20 x V 2 x 1000 / V 1 x 20 mg of CaCO 3

= 1000 x V 2 / V 1 mg of CaCO3

Total hardness of given water sample = ---------------------ppm









17



DETERMINATION OF TOTAL HARDNESS

Pipette out 20ml of sample hard water into a clean conical flask. Add 5ml of buffer solution and 4 -5
drops of Eriochrome black -T indicator. Titrate the wine - red coloured solution with EDTA from the burette until
the colour steel blue appears at the end point. Repeat the titration for concordant values. Let the titre value be
V 2ml.



DETERMINATION OF PERMANENT HARDNESS

Take 100ml of hard water sample in a 500ml beaker and boil gently for about 1hour. Cool, filter it into a
100ml standard flask and make the volume up to the mark. Take 20ml of this solution and proceed it in the same
way as in titration (I). The volume of EDTA consumed corresponds to the permanent hardness of the water
sample. Let the titre value be V 3ml. Temporary hardness is calculated by subtracting permanent hardness from
total hardness.





















18




DETERMINATION OF PERMANENT HARDNESS
BOILED SAMPLE WATER Vs Std. EDTA Indicator: EBT


S.No.
Volume of boiled
hard water (ml)
Burette Reading (ml) Volume of
EDTA
(ml)

Concordant value

Initial Final



CALCULATION OF PERMANENT HARDNESS


Volume of EDTA consumed V 3 = ---------------------ml

1ml of EDTA = 20 / V 1 mg of CaCO 3

V 3ml of EDTA = 20 / V 1 x V 3 mg of CaCO 3

(i.e) 20 ml of boiled sample hard water = 20 / V 1 x V 3 mg of CaCO 3

Then 1000ml of boiled water sample = 20 / V 1 x V 3 / 20 * 1000mg of CaCO 3

= 1000 x V 3 / V 1 mg of CaCO 3

permanent hardness of boiled water sample = -----------------ppm

Temporary hardness of the given water sample = Total hardness ? Permanent hardness

= ------------------ppm

19







RESULT

(i) Total hardness of the given sample water = -------------- ppm.
(ii) Permanent hardness of the given sample water = --------------- ppm.
(iii) Temporary hardness of the given sample water = ----------------ppm.







VIVA-VOCE

1. Define ? Hard water
2. What is the structure of EDTA?
3. How will you calculate temporary hardness?
4. What is the role of the buffer in EDTA titration?
5. What is the permissible limit of hardness in drinking water?
6. Name the hardness producing ions present in water.
7. Name two salts which are responsible for temporary hardness.
8. Why is CaCO 3 taken as the standard?
9. Write the expansion of EDTA.
10. What is meant by EBT?











20





SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II
Standardisation of
AgNO 3
Estimation of Chloride
Burette solution

AgNO 3 solution

Std. AgNO 3 solution

Pipette solution

20ml std KCl solution

20 ml water sample

Indicator

1ml K 2CrO 4

1ml K 2CrO 4


End point

yellow to reddish brown

yellow to reddish brown

Titration I
Std. AgNO3 Vs KCl Indicator: Potassium Chromate













CALCULATION

Volume of KCl (V 1) = ------- ml

Strength of KCl (N 1) = ------- N

Volume of Silver Nitrate (V 2) = -------- ml

Strength of Siver Nitrate V 1N 1
N 2 =
V 1

= --------------------- N

S.No.
Volume of KCl
(ml)
Burette Reading (ml)
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

21




Expt.No. 3 ESTIMATION OF CHLORIDE CONTENT IN WATER
(ARGENTOMETRIC METHOD)
AIM
To estimate the amount of chloride present in given water sample by Argentometric method (Mohr?s
method). You are provided with standard solution of NaCl of strength --------N and a approximately N/10 solution of
Silver nitrate.

PRINCIPLE
The Chloride ion in the form of NaCl, KCl, CaCl 2, MgCl 2 etc., present in the water sample can be estimated
by Argentometric method or known as Mohr?s method. It is an example for precipitation titration. The reaction
between std. Sodium chloride and Silver nitrate is given below.
AgNO 3 + NaCl ? AgCl ? + NaNO 3
The completion of reaction can be observed by employing potassium chromate as the indicator. The end
point is the colour change from yellow to reddish brown due to the following reaction.
2AgNO 3 + K 2CrO 4 ? Ag 2CrO 4 ? + 2KNO 3
Potassium chromate indicator will not be precipitated as silver chromate until all the chlorides in the solution
have been precipitated as AgCl Since a precipitation reaction takes place in preference, this reaction takes place
only at the end point.

PROCEDURE
TITRATION I: STANDARDISATION OF SILVER NITRATE
Pipette out 20ml of standard sodium or potassium chloride solution into a clean conical flask. Add 1ml of 5%
K 2CrO 4 indicator, as the solution turns yellow in colour. Titrate it against silver nitrate solution taken in the burette.
Observe the nearness of the end point through the formation of coagulated silver chloride precipitate at the bottom
of the flask. Now add the silver nitrate drop by drop until the solution gets a faint reddish brown tinge. Repeat the
titration for concordant value. Let the volume of silver nitrate be V 2ml.





22






TITRATION - II

Std AgNO3 Vs WATER SAMPLE Indicator: Potassium Chromate













CALCULATION

Volume of Silver Nitrate (V 3) = ------------ ml

Strength of Siver Nitrate (N 3) = ------------- N

Volume of Water sample (V 4) = -------------- ml

Strength of Water sample V 3 N 3
(N 4) =
V 4

= ----------------- N

Amount of Chloride ion present in 1000 ml of the water sample = Equivalent mass of HCl X 1000


= N 4 x 35.46 x 1000


= -----------------mg/l







S.No.
Volume of water
sample (ml)
Burette Reading
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

FirstRanker.com - FirstRanker's Choice



?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





3


PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)
1. Fundamentals
To provide students with a solid foundation in Mathematics, Science and fundamentals of engineering,
enabling them to apply, to find solutions for engineering problems and use this knowledge to acquire higher
education
2. Core Competence
To train the students in chemistry practicals so that they apply their knowledge and training to compare,
and to analyze various engineering industrial problems to find solutions
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice this enables
them to find solutions for the real time problems in industry, and to design products
4. Professionalism
To inculcate professional and effective communication skills, leadership qualities and team spirit in the
students to make them multi-faceted personalities and develop their ability to relate engineering issues to
broader social context
5. Lifelong Learning/Ethics
To demonstrate and practice ethical and professional responsibilities in the industry and society in the
large, through commitment and lifelong learning needed for successful professional career






4


PROGRAMME OUTCOMES (POs)
To demonstrate and apply knowledge of Mathematics, Science and engineering fundamentals in the following
experiments.
1 .To estimate HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. To determine total, temporary & permanent hardness of water by EDTA method.
3. To determine DO content of water sample by Winkler?s method.
4. To determine chloride content of water sample by Argentometric method.
5. To estimate copper content of the given solution by Iodometry.
6. To determine strength of given hydrochloric acid using pH meter.
7. To determine strength of acids in a mixture of acids using conductivity meter.
8. To determine iron content of the given solution using potentiometer.
9. To estimate iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. To estimate sodium and potassium present in water using flame photometer.
11. To determine molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. To determine Pseudo first order kinetics ? ester hydrolysis.
13. To determine Corrosion experiment ? weight loss method.
14. To estimate CMC.
15. To estimate Phase change in a solid.
16. To determine strength of strong acid vs strong base using conductivity meter.











5

BS8161 - CHEMISTRY LABORATORY
SYLLABUS


? To make the student to acquire practical skills in the determination of water quality
parameters through volumetric and instrumental analysis.

? ???? ??? ???? ?? ???? ? ? ?To acquaint the students with the determination of molecular weight of a polymer by
viscometery.

LIST OF EXPERIMENTS:
1. Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. Determination of total, temporary & permanent hardness of water by EDTA method.
3. Determination of DO content of water sample by Winkler?s method.
4. Determination of chloride content of water sample by Argentometric method.
5. Estimation of copper content of the given solution by Iodometry.
6. Determination of strength of given hydrochloric acid using pH meter.
7. Determination of strength of acids in a mixture of acids using conductivity meter.
8. Estimation of iron content of the given solution using potentiometer.
9. Estimation of iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. Estimation of sodium and potassium present in water using flame photometer.
11. Determination of molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. Pseudo first order kinetics ? ester hydrolysis.
13. Corrosion experiment ? weight loss method.
14. Determination of CMC.
15. Phase change in a solid.
16. Conductometric titration of strong acid vs strong base.




? The students will be outfitted with hands-on knowledge in the quantitative chemical
analysis of water quality related parameters.
COURSE OBJECTIVES
COURSE OUTCOMES
6


INDEX [ SEMESTER ? I ]


S.No.



Date


Experiment

Date of
submission



Mark


Signature

1.

Estimation of HCl using Na 2CO 3 as
primary standard and Determination of
alkalinity in water sample.



2.


Determination of total, temporary &
permanent hardness of water by EDTA
method.



3.


Determination of chloride content of water
sample by argentometric method.



4.


Determination of strength of given
hydrochloric acid using pH meter.



5.


Determination of strength of acids in a
mixture of acids using conductivity meter.



6.


Estimation of iron content of the given
solution using potentiometer.



7.





Conductometric titration of strong acid Vs
strong base.



8.



Estimation of copper content of the given
solution by Iodometry


9.
Estimation of sodium and potassium
present in water using flame photometer




7




CONTENTS


S.No.


NAME OF EXPERIMENT

PAGE
No.
SEMESTER - I
1.
Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in
water sample.
09
2. Determination of total, temporary & permanent hardness of water by EDTA method. 15
3. Determination of chloride content of water sample by Argentometric method. 21
4. Determination of strength of given hydrochloric acid using pH meter. 25
5. Determination of strength of acids in a mixture of acids using conductivity meter. 29
6. Estimation of iron content of the given solution using potentiometer. 33
7. Conductometric titration of strong acid Vs strong base.

39


42

8


Estimation of copper content of the given solution by Iodometry 43
9 Estimation of sodium and potassium present in water using flame photometer 47






8



SHORT PROCEDURE:

CONTENTS
TITRATION
Estimation of alkalinity in water sample
(Std HCl Vs water sample)

Burette solution

Std. HCl


Pipette solution

Water sample


Indicator


(i) Phenolphthalein
(ii) Methyl orange


End point

(i) Disappearance of pink colour
(ii) Appearance of reddish orange colour






Relationship
between P &M
Nature of alkalinity
Amount of individual
alkalinities
OH
-
HCO 3
-


CO 3
2-

P = M

only OH
-

P or M

?
0.0

0.0


2P = M

only CO 3
2-


2P or M


0.0


0.0


?

P =0, M?0

only HCO 3
-



M



0.0



?

0.0


2P > M


OH
-
&CO 3
2-


OH
-
= 2P-M
CO 3
2-
= 2(M-P)


?

0.0

?

P < ? M




HCO 3
-
&CO 3
2-


HCO 3
-
= M-2P
CO 3
2-
= 2P

0.0 ? ?




9





Expt. No. 1 DETERMINATION OF ALKALINITY IN WATER
AIM
To determine the type and amounts of alkalinity in the given water sample. A standard solution of Na 2CO 3
of strength ____N is given.

PRINCIPLE
Alkalinity in water is due to the presence of soluble hydroxides, bicarbonates and carbonates.
Determination of various types and amounts of alkalinity is easily carried out by titration with standard HCl
employing the indicators phenolphthalein and methyl orange independently or in succession.

The following reactions occur when different types of alkalinity are neutralized with acid.

OH
?
+ H
+
? H 2O completed at pH 8.2-9.0 ----- (1)

CO 3
2 ?
+ H
+
? HCO 3
?
----- (2)

HCO 3
?
+ H
+
? (H 2CO 3) ? H 2O + CO 2, completed at pH 4.2-5.5 ----- (3)

Neutralisation (1) & (2) will be notified by phenolphthalein end-point while all the three will be

accounted by
methyl orange end-point. Bicarbonate in eqn. (3) may be due to the existence of soluble free bicarbonate salts and
bicarbonates resulting from half neutralization of soluble carbonates (eqn. (2))

Various steps to be followed

a) A known volume of water sample is titrated against std. HCl using first phenolphthalein indicator till
end-point (P) and the titration is continued without break using methyl orange indicator till the end-
point (M).



10


Titration

Estimation of Alkalinity in water sample

Standard HCl Vs Water sample Indicator: 1. Phenolphthalein
2. Methyl Orange


S.No.
Volume
of water
sample (ml)
Burette Reading
Concordant value

Initial Phenolphthalein End
Point (P)
Methyl Orange End
Point (M)

1

2






CALCULATION

Hydroxide ion alkalinity
Volume of HCl (2P-M) = ???????ml

Strength of HCl = ???????? N

Volume of water sample = ???????...ml

Strength of water sample = Volume of HCl (2P-M) x Strength of HCl
Volume of water sample

=

? Hydroxide ion alkalinity in terms of
CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ??????.mg/l







11




b) From the magnitudes of the P & M, the nature of alkalinity can be arrived as follows:

(i) P = M => Presence of only OH
-

(ii) 2P = M => Presence of only CO 3
2-

(iii) P =0, M=0 => Presence of only HCO 3
-
(iv) 2P > M => Presence of OH
-
& CO 3
2-
(v) 2P < M => Presence of HCO 3
-
& CO 3
2-

(Mixture of OH
-
& HCO3
-
is not listed since they do not exist together and are considered equivalent to CO 3
2-
).

PROCEDURE
TITRATION
ESTIMATION OF ALKALINITY IN WATER SAMPLE

Exactly 20 ml of water sample is pipetted out into a clean conical flask. Few drops of phenolphthalein
indicator are added and titrated against a standardized HCl taken in the burette. The end point is the
disappearance of pink colour, which is noted as P. Few drops of methyl orange indicator is added to the same
solution. The solution turns to yellow. The titration is continued further by adding same HCl without break till the
end point is reached. The end point is the colour change from yellow to reddish orange.

The experiment is repeated to get concordant values. From the magnitudes of P & M values, the type of
alkalinity present in the water sample is inferred and the individual amounts are calculated and reported.










12


Carbonate ion alkalinity

Volume of HCl 2 (M ? P) = ??? ????????ml

Strength of HCl = ??.?????..???...N

Volume of water sample =........................................ml

Strength of water sample = Volume of HCl 2 (M ? P) x Strength of HCl
Volume of water sample

= ???????????.. N




? Carbonate ion alkalinity
in terms of CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ???????????mg/l

















13





RESULT

1) The type of alkalinity present in the water sample = -------------------------ions.

2) The individual amounts of alkalinity present in the water sample:
Hydroxide ion alkalinity

= ----------------- ppm
Carbonate ion alkalinity = ------------------ ppm
Bicarbonate ion alkalinity = ----------------- ppm





VIVA-VOCE


1. What is meant by alkalinity?
2. What are the ions responsible for alkalinity?
3. Why OH
-
and HCO 3
?
ions cannot exist together in water?
4. What are the ions responsible for alkalinity when 2P > M?
5. What is the pH range for both in acidic and basic solutions?
6. What is the colour of phenolphthalein in an acid and in an alkaline solution?
7. What is the purpose of using two indicators in same titration?
8. What are the possible combinations of ions for alkalinity?
9. How is the amount of alkalinity expressed?
10. What are the types of indicator used in this experiment?







14

SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II TITRATION III
Standardisation of
EDTA
(EDTA Vs Std
Hard water)
Determination of
total hardness
(Std EDTA Vs Hard
water sample)
Determination of
permanent hardness
(Std EDTA Vs Boiled
Hard water sample)

Burette solution

EDTA solution

EDTA solution

EDTA solution

Pipette solution

20ml Std. hard water

20 ml hard water sample

20ml boiled hard water sample

Indicator

2 drops of EBT

2 drops of EBT

2 drops of EBT

Additional soln.


Ammoniacal Buffer
solution (5ml)

Ammoniacal Buffer solution
(5ml)

Ammoniacal Buffer solution
(5ml)
End point Wine - red to Steel blue Wine - red to steel blue Wine - red to Steel blue




STANDARDISATION OF EDTA
Titration - I
Std. HARD WATER Vs EDTA Indicator: EBT

S. No.
Volume of std hard
water (ml)
Burette Reading Volume of
EDTA
(V 1) (ml)
Concordant value

Initial

Final



Volume of std .hard water taken = 20 ml
Volume of EDTA consumed (V 1) = --------------- ml
1 ml of std.hard water = 1mg of CaCO 3
20 ml of std hard water = 20 mg of CaCO 3

V 1 ml of EDTA solution containing 20 mg of CaCO 3
1 ml of EDTA solution = 20 / V 1 mg of CaCO 3
= -----------------------mg of CaCO 3


15

Expt. No. 2 DETERMINATION OF TOTAL, TEMPORARY AND
PERMANENT HARDNESS OF WATER

AIM
To estimate the amount of total, temporary & permanent hardness in the given sample of water.

PRINCIPLE
The estimation is based on the complexometric titration.

(i) Total hardness of water is estimated by titrating against EDTA using EBT indicator.
EBT+M ?[EBT-M] (unstable complex)
(EBT-M) (Unstable complex) +EDTA ? [EDTA-M] (stable complex) +EBT
EBT indicator forms wine- red colored complex with metal ions present in water. On addition of EDTA
metal ions preferably forms complexes with EDTA and steel blue EBT indicator is set free. Therefore
change of colour from wine- red to steel blue denotes the end point.

(ii) Temporary hardness is removed by boiling the water.
Ca (HCO 3) 2 ? CaCO 3 +CO 2 ?+H 2O
Mg (HCO 3) 2 ? Mg(OH) 2 +2CO 2 ?
The precipitate is filtered and the remaining permanent hardness is estimated using EDTA.

PROCEDURE

TITRATION ? I
STANDARDISATION OF EDTA

Pipette out 20ml of standard hard water into a 250ml conical flask. Add 5ml of buffer solution and 3
drops of eriochrome black T indictor. Titrate the solution with EDTA from the burette until the colour
changes from wine- red to steel blue at the end point. Repeat the titration for concordant values. Let the
titre value be V 1ml.


16


Titration-II
SAMPLE HARD WATER Vs Std EDTA Indicator: EBT

S.No. Volume of sample
hard water (ml)
Burette Reading Volume of
EDTA
(V 2) (ml)
Concordant value

Initial

Final




CALCULATION

Calculation of total hardness


Volume of EDTA consumed (V 2) = ------------------------- ml
1ml of EDTA = 20 / V 1 mg of CaCO 3
V 2 ml of EDTA = 20 / V 1 x V 2 mg of CaCO 3

( i.e), If 20ml of sample hard water contains 20 x V 2 mg of CaCO 3 / V 1

Then 1000ml of water sample = 20 x V 2 x 1000 / V 1 x 20 mg of CaCO 3

= 1000 x V 2 / V 1 mg of CaCO3

Total hardness of given water sample = ---------------------ppm









17



DETERMINATION OF TOTAL HARDNESS

Pipette out 20ml of sample hard water into a clean conical flask. Add 5ml of buffer solution and 4 -5
drops of Eriochrome black -T indicator. Titrate the wine - red coloured solution with EDTA from the burette until
the colour steel blue appears at the end point. Repeat the titration for concordant values. Let the titre value be
V 2ml.



DETERMINATION OF PERMANENT HARDNESS

Take 100ml of hard water sample in a 500ml beaker and boil gently for about 1hour. Cool, filter it into a
100ml standard flask and make the volume up to the mark. Take 20ml of this solution and proceed it in the same
way as in titration (I). The volume of EDTA consumed corresponds to the permanent hardness of the water
sample. Let the titre value be V 3ml. Temporary hardness is calculated by subtracting permanent hardness from
total hardness.





















18




DETERMINATION OF PERMANENT HARDNESS
BOILED SAMPLE WATER Vs Std. EDTA Indicator: EBT


S.No.
Volume of boiled
hard water (ml)
Burette Reading (ml) Volume of
EDTA
(ml)

Concordant value

Initial Final



CALCULATION OF PERMANENT HARDNESS


Volume of EDTA consumed V 3 = ---------------------ml

1ml of EDTA = 20 / V 1 mg of CaCO 3

V 3ml of EDTA = 20 / V 1 x V 3 mg of CaCO 3

(i.e) 20 ml of boiled sample hard water = 20 / V 1 x V 3 mg of CaCO 3

Then 1000ml of boiled water sample = 20 / V 1 x V 3 / 20 * 1000mg of CaCO 3

= 1000 x V 3 / V 1 mg of CaCO 3

permanent hardness of boiled water sample = -----------------ppm

Temporary hardness of the given water sample = Total hardness ? Permanent hardness

= ------------------ppm

19







RESULT

(i) Total hardness of the given sample water = -------------- ppm.
(ii) Permanent hardness of the given sample water = --------------- ppm.
(iii) Temporary hardness of the given sample water = ----------------ppm.







VIVA-VOCE

1. Define ? Hard water
2. What is the structure of EDTA?
3. How will you calculate temporary hardness?
4. What is the role of the buffer in EDTA titration?
5. What is the permissible limit of hardness in drinking water?
6. Name the hardness producing ions present in water.
7. Name two salts which are responsible for temporary hardness.
8. Why is CaCO 3 taken as the standard?
9. Write the expansion of EDTA.
10. What is meant by EBT?











20





SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II
Standardisation of
AgNO 3
Estimation of Chloride
Burette solution

AgNO 3 solution

Std. AgNO 3 solution

Pipette solution

20ml std KCl solution

20 ml water sample

Indicator

1ml K 2CrO 4

1ml K 2CrO 4


End point

yellow to reddish brown

yellow to reddish brown

Titration I
Std. AgNO3 Vs KCl Indicator: Potassium Chromate













CALCULATION

Volume of KCl (V 1) = ------- ml

Strength of KCl (N 1) = ------- N

Volume of Silver Nitrate (V 2) = -------- ml

Strength of Siver Nitrate V 1N 1
N 2 =
V 1

= --------------------- N

S.No.
Volume of KCl
(ml)
Burette Reading (ml)
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

21




Expt.No. 3 ESTIMATION OF CHLORIDE CONTENT IN WATER
(ARGENTOMETRIC METHOD)
AIM
To estimate the amount of chloride present in given water sample by Argentometric method (Mohr?s
method). You are provided with standard solution of NaCl of strength --------N and a approximately N/10 solution of
Silver nitrate.

PRINCIPLE
The Chloride ion in the form of NaCl, KCl, CaCl 2, MgCl 2 etc., present in the water sample can be estimated
by Argentometric method or known as Mohr?s method. It is an example for precipitation titration. The reaction
between std. Sodium chloride and Silver nitrate is given below.
AgNO 3 + NaCl ? AgCl ? + NaNO 3
The completion of reaction can be observed by employing potassium chromate as the indicator. The end
point is the colour change from yellow to reddish brown due to the following reaction.
2AgNO 3 + K 2CrO 4 ? Ag 2CrO 4 ? + 2KNO 3
Potassium chromate indicator will not be precipitated as silver chromate until all the chlorides in the solution
have been precipitated as AgCl Since a precipitation reaction takes place in preference, this reaction takes place
only at the end point.

PROCEDURE
TITRATION I: STANDARDISATION OF SILVER NITRATE
Pipette out 20ml of standard sodium or potassium chloride solution into a clean conical flask. Add 1ml of 5%
K 2CrO 4 indicator, as the solution turns yellow in colour. Titrate it against silver nitrate solution taken in the burette.
Observe the nearness of the end point through the formation of coagulated silver chloride precipitate at the bottom
of the flask. Now add the silver nitrate drop by drop until the solution gets a faint reddish brown tinge. Repeat the
titration for concordant value. Let the volume of silver nitrate be V 2ml.





22






TITRATION - II

Std AgNO3 Vs WATER SAMPLE Indicator: Potassium Chromate













CALCULATION

Volume of Silver Nitrate (V 3) = ------------ ml

Strength of Siver Nitrate (N 3) = ------------- N

Volume of Water sample (V 4) = -------------- ml

Strength of Water sample V 3 N 3
(N 4) =
V 4

= ----------------- N

Amount of Chloride ion present in 1000 ml of the water sample = Equivalent mass of HCl X 1000


= N 4 x 35.46 x 1000


= -----------------mg/l







S.No.
Volume of water
sample (ml)
Burette Reading
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

23





TITRATION - II
ESTIMATION OF CHLORIDE ION

Pipette out 40 ml of the given water sample into a clean conical flask.To this sample add 1ml of 5% K 2CrO 4
indicator and titrate it against the standardized silver nitrate solution taken in the burette and continue the titration
until the solution produces a reddish brown colour. Note down the end point and repeat the titration for
concordance. Let the volume be V 3ml.







RESULT

The amount of chloride ion present in the water sample = ----------------- mg/l.




VIVA-VOCE

1. Why is this method known as Argentometric method?
2.
What is the chemical reaction between AgNO 3 and Cl
-
ions present in water?

3.
What is the form of Chloride ion present in water?

4. What is the reaction between AgNO 3 and K 2CrO 4 ?
5. What is the name of the method used in this titration?
6. Name the link solution used in the determination.
7. Name the solution used to standardize AgNO 3.
8. What is the indicator used in the determination?
9. How will you calculate the amount of chloride ion in the given solution?
10. What is the colour change in the titration?




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DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





3


PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)
1. Fundamentals
To provide students with a solid foundation in Mathematics, Science and fundamentals of engineering,
enabling them to apply, to find solutions for engineering problems and use this knowledge to acquire higher
education
2. Core Competence
To train the students in chemistry practicals so that they apply their knowledge and training to compare,
and to analyze various engineering industrial problems to find solutions
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice this enables
them to find solutions for the real time problems in industry, and to design products
4. Professionalism
To inculcate professional and effective communication skills, leadership qualities and team spirit in the
students to make them multi-faceted personalities and develop their ability to relate engineering issues to
broader social context
5. Lifelong Learning/Ethics
To demonstrate and practice ethical and professional responsibilities in the industry and society in the
large, through commitment and lifelong learning needed for successful professional career






4


PROGRAMME OUTCOMES (POs)
To demonstrate and apply knowledge of Mathematics, Science and engineering fundamentals in the following
experiments.
1 .To estimate HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. To determine total, temporary & permanent hardness of water by EDTA method.
3. To determine DO content of water sample by Winkler?s method.
4. To determine chloride content of water sample by Argentometric method.
5. To estimate copper content of the given solution by Iodometry.
6. To determine strength of given hydrochloric acid using pH meter.
7. To determine strength of acids in a mixture of acids using conductivity meter.
8. To determine iron content of the given solution using potentiometer.
9. To estimate iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. To estimate sodium and potassium present in water using flame photometer.
11. To determine molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. To determine Pseudo first order kinetics ? ester hydrolysis.
13. To determine Corrosion experiment ? weight loss method.
14. To estimate CMC.
15. To estimate Phase change in a solid.
16. To determine strength of strong acid vs strong base using conductivity meter.











5

BS8161 - CHEMISTRY LABORATORY
SYLLABUS


? To make the student to acquire practical skills in the determination of water quality
parameters through volumetric and instrumental analysis.

? ???? ??? ???? ?? ???? ? ? ?To acquaint the students with the determination of molecular weight of a polymer by
viscometery.

LIST OF EXPERIMENTS:
1. Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. Determination of total, temporary & permanent hardness of water by EDTA method.
3. Determination of DO content of water sample by Winkler?s method.
4. Determination of chloride content of water sample by Argentometric method.
5. Estimation of copper content of the given solution by Iodometry.
6. Determination of strength of given hydrochloric acid using pH meter.
7. Determination of strength of acids in a mixture of acids using conductivity meter.
8. Estimation of iron content of the given solution using potentiometer.
9. Estimation of iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. Estimation of sodium and potassium present in water using flame photometer.
11. Determination of molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. Pseudo first order kinetics ? ester hydrolysis.
13. Corrosion experiment ? weight loss method.
14. Determination of CMC.
15. Phase change in a solid.
16. Conductometric titration of strong acid vs strong base.




? The students will be outfitted with hands-on knowledge in the quantitative chemical
analysis of water quality related parameters.
COURSE OBJECTIVES
COURSE OUTCOMES
6


INDEX [ SEMESTER ? I ]


S.No.



Date


Experiment

Date of
submission



Mark


Signature

1.

Estimation of HCl using Na 2CO 3 as
primary standard and Determination of
alkalinity in water sample.



2.


Determination of total, temporary &
permanent hardness of water by EDTA
method.



3.


Determination of chloride content of water
sample by argentometric method.



4.


Determination of strength of given
hydrochloric acid using pH meter.



5.


Determination of strength of acids in a
mixture of acids using conductivity meter.



6.


Estimation of iron content of the given
solution using potentiometer.



7.





Conductometric titration of strong acid Vs
strong base.



8.



Estimation of copper content of the given
solution by Iodometry


9.
Estimation of sodium and potassium
present in water using flame photometer




7




CONTENTS


S.No.


NAME OF EXPERIMENT

PAGE
No.
SEMESTER - I
1.
Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in
water sample.
09
2. Determination of total, temporary & permanent hardness of water by EDTA method. 15
3. Determination of chloride content of water sample by Argentometric method. 21
4. Determination of strength of given hydrochloric acid using pH meter. 25
5. Determination of strength of acids in a mixture of acids using conductivity meter. 29
6. Estimation of iron content of the given solution using potentiometer. 33
7. Conductometric titration of strong acid Vs strong base.

39


42

8


Estimation of copper content of the given solution by Iodometry 43
9 Estimation of sodium and potassium present in water using flame photometer 47






8



SHORT PROCEDURE:

CONTENTS
TITRATION
Estimation of alkalinity in water sample
(Std HCl Vs water sample)

Burette solution

Std. HCl


Pipette solution

Water sample


Indicator


(i) Phenolphthalein
(ii) Methyl orange


End point

(i) Disappearance of pink colour
(ii) Appearance of reddish orange colour






Relationship
between P &M
Nature of alkalinity
Amount of individual
alkalinities
OH
-
HCO 3
-


CO 3
2-

P = M

only OH
-

P or M

?
0.0

0.0


2P = M

only CO 3
2-


2P or M


0.0


0.0


?

P =0, M?0

only HCO 3
-



M



0.0



?

0.0


2P > M


OH
-
&CO 3
2-


OH
-
= 2P-M
CO 3
2-
= 2(M-P)


?

0.0

?

P < ? M




HCO 3
-
&CO 3
2-


HCO 3
-
= M-2P
CO 3
2-
= 2P

0.0 ? ?




9





Expt. No. 1 DETERMINATION OF ALKALINITY IN WATER
AIM
To determine the type and amounts of alkalinity in the given water sample. A standard solution of Na 2CO 3
of strength ____N is given.

PRINCIPLE
Alkalinity in water is due to the presence of soluble hydroxides, bicarbonates and carbonates.
Determination of various types and amounts of alkalinity is easily carried out by titration with standard HCl
employing the indicators phenolphthalein and methyl orange independently or in succession.

The following reactions occur when different types of alkalinity are neutralized with acid.

OH
?
+ H
+
? H 2O completed at pH 8.2-9.0 ----- (1)

CO 3
2 ?
+ H
+
? HCO 3
?
----- (2)

HCO 3
?
+ H
+
? (H 2CO 3) ? H 2O + CO 2, completed at pH 4.2-5.5 ----- (3)

Neutralisation (1) & (2) will be notified by phenolphthalein end-point while all the three will be

accounted by
methyl orange end-point. Bicarbonate in eqn. (3) may be due to the existence of soluble free bicarbonate salts and
bicarbonates resulting from half neutralization of soluble carbonates (eqn. (2))

Various steps to be followed

a) A known volume of water sample is titrated against std. HCl using first phenolphthalein indicator till
end-point (P) and the titration is continued without break using methyl orange indicator till the end-
point (M).



10


Titration

Estimation of Alkalinity in water sample

Standard HCl Vs Water sample Indicator: 1. Phenolphthalein
2. Methyl Orange


S.No.
Volume
of water
sample (ml)
Burette Reading
Concordant value

Initial Phenolphthalein End
Point (P)
Methyl Orange End
Point (M)

1

2






CALCULATION

Hydroxide ion alkalinity
Volume of HCl (2P-M) = ???????ml

Strength of HCl = ???????? N

Volume of water sample = ???????...ml

Strength of water sample = Volume of HCl (2P-M) x Strength of HCl
Volume of water sample

=

? Hydroxide ion alkalinity in terms of
CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ??????.mg/l







11




b) From the magnitudes of the P & M, the nature of alkalinity can be arrived as follows:

(i) P = M => Presence of only OH
-

(ii) 2P = M => Presence of only CO 3
2-

(iii) P =0, M=0 => Presence of only HCO 3
-
(iv) 2P > M => Presence of OH
-
& CO 3
2-
(v) 2P < M => Presence of HCO 3
-
& CO 3
2-

(Mixture of OH
-
& HCO3
-
is not listed since they do not exist together and are considered equivalent to CO 3
2-
).

PROCEDURE
TITRATION
ESTIMATION OF ALKALINITY IN WATER SAMPLE

Exactly 20 ml of water sample is pipetted out into a clean conical flask. Few drops of phenolphthalein
indicator are added and titrated against a standardized HCl taken in the burette. The end point is the
disappearance of pink colour, which is noted as P. Few drops of methyl orange indicator is added to the same
solution. The solution turns to yellow. The titration is continued further by adding same HCl without break till the
end point is reached. The end point is the colour change from yellow to reddish orange.

The experiment is repeated to get concordant values. From the magnitudes of P & M values, the type of
alkalinity present in the water sample is inferred and the individual amounts are calculated and reported.










12


Carbonate ion alkalinity

Volume of HCl 2 (M ? P) = ??? ????????ml

Strength of HCl = ??.?????..???...N

Volume of water sample =........................................ml

Strength of water sample = Volume of HCl 2 (M ? P) x Strength of HCl
Volume of water sample

= ???????????.. N




? Carbonate ion alkalinity
in terms of CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ???????????mg/l

















13





RESULT

1) The type of alkalinity present in the water sample = -------------------------ions.

2) The individual amounts of alkalinity present in the water sample:
Hydroxide ion alkalinity

= ----------------- ppm
Carbonate ion alkalinity = ------------------ ppm
Bicarbonate ion alkalinity = ----------------- ppm





VIVA-VOCE


1. What is meant by alkalinity?
2. What are the ions responsible for alkalinity?
3. Why OH
-
and HCO 3
?
ions cannot exist together in water?
4. What are the ions responsible for alkalinity when 2P > M?
5. What is the pH range for both in acidic and basic solutions?
6. What is the colour of phenolphthalein in an acid and in an alkaline solution?
7. What is the purpose of using two indicators in same titration?
8. What are the possible combinations of ions for alkalinity?
9. How is the amount of alkalinity expressed?
10. What are the types of indicator used in this experiment?







14

SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II TITRATION III
Standardisation of
EDTA
(EDTA Vs Std
Hard water)
Determination of
total hardness
(Std EDTA Vs Hard
water sample)
Determination of
permanent hardness
(Std EDTA Vs Boiled
Hard water sample)

Burette solution

EDTA solution

EDTA solution

EDTA solution

Pipette solution

20ml Std. hard water

20 ml hard water sample

20ml boiled hard water sample

Indicator

2 drops of EBT

2 drops of EBT

2 drops of EBT

Additional soln.


Ammoniacal Buffer
solution (5ml)

Ammoniacal Buffer solution
(5ml)

Ammoniacal Buffer solution
(5ml)
End point Wine - red to Steel blue Wine - red to steel blue Wine - red to Steel blue




STANDARDISATION OF EDTA
Titration - I
Std. HARD WATER Vs EDTA Indicator: EBT

S. No.
Volume of std hard
water (ml)
Burette Reading Volume of
EDTA
(V 1) (ml)
Concordant value

Initial

Final



Volume of std .hard water taken = 20 ml
Volume of EDTA consumed (V 1) = --------------- ml
1 ml of std.hard water = 1mg of CaCO 3
20 ml of std hard water = 20 mg of CaCO 3

V 1 ml of EDTA solution containing 20 mg of CaCO 3
1 ml of EDTA solution = 20 / V 1 mg of CaCO 3
= -----------------------mg of CaCO 3


15

Expt. No. 2 DETERMINATION OF TOTAL, TEMPORARY AND
PERMANENT HARDNESS OF WATER

AIM
To estimate the amount of total, temporary & permanent hardness in the given sample of water.

PRINCIPLE
The estimation is based on the complexometric titration.

(i) Total hardness of water is estimated by titrating against EDTA using EBT indicator.
EBT+M ?[EBT-M] (unstable complex)
(EBT-M) (Unstable complex) +EDTA ? [EDTA-M] (stable complex) +EBT
EBT indicator forms wine- red colored complex with metal ions present in water. On addition of EDTA
metal ions preferably forms complexes with EDTA and steel blue EBT indicator is set free. Therefore
change of colour from wine- red to steel blue denotes the end point.

(ii) Temporary hardness is removed by boiling the water.
Ca (HCO 3) 2 ? CaCO 3 +CO 2 ?+H 2O
Mg (HCO 3) 2 ? Mg(OH) 2 +2CO 2 ?
The precipitate is filtered and the remaining permanent hardness is estimated using EDTA.

PROCEDURE

TITRATION ? I
STANDARDISATION OF EDTA

Pipette out 20ml of standard hard water into a 250ml conical flask. Add 5ml of buffer solution and 3
drops of eriochrome black T indictor. Titrate the solution with EDTA from the burette until the colour
changes from wine- red to steel blue at the end point. Repeat the titration for concordant values. Let the
titre value be V 1ml.


16


Titration-II
SAMPLE HARD WATER Vs Std EDTA Indicator: EBT

S.No. Volume of sample
hard water (ml)
Burette Reading Volume of
EDTA
(V 2) (ml)
Concordant value

Initial

Final




CALCULATION

Calculation of total hardness


Volume of EDTA consumed (V 2) = ------------------------- ml
1ml of EDTA = 20 / V 1 mg of CaCO 3
V 2 ml of EDTA = 20 / V 1 x V 2 mg of CaCO 3

( i.e), If 20ml of sample hard water contains 20 x V 2 mg of CaCO 3 / V 1

Then 1000ml of water sample = 20 x V 2 x 1000 / V 1 x 20 mg of CaCO 3

= 1000 x V 2 / V 1 mg of CaCO3

Total hardness of given water sample = ---------------------ppm









17



DETERMINATION OF TOTAL HARDNESS

Pipette out 20ml of sample hard water into a clean conical flask. Add 5ml of buffer solution and 4 -5
drops of Eriochrome black -T indicator. Titrate the wine - red coloured solution with EDTA from the burette until
the colour steel blue appears at the end point. Repeat the titration for concordant values. Let the titre value be
V 2ml.



DETERMINATION OF PERMANENT HARDNESS

Take 100ml of hard water sample in a 500ml beaker and boil gently for about 1hour. Cool, filter it into a
100ml standard flask and make the volume up to the mark. Take 20ml of this solution and proceed it in the same
way as in titration (I). The volume of EDTA consumed corresponds to the permanent hardness of the water
sample. Let the titre value be V 3ml. Temporary hardness is calculated by subtracting permanent hardness from
total hardness.





















18




DETERMINATION OF PERMANENT HARDNESS
BOILED SAMPLE WATER Vs Std. EDTA Indicator: EBT


S.No.
Volume of boiled
hard water (ml)
Burette Reading (ml) Volume of
EDTA
(ml)

Concordant value

Initial Final



CALCULATION OF PERMANENT HARDNESS


Volume of EDTA consumed V 3 = ---------------------ml

1ml of EDTA = 20 / V 1 mg of CaCO 3

V 3ml of EDTA = 20 / V 1 x V 3 mg of CaCO 3

(i.e) 20 ml of boiled sample hard water = 20 / V 1 x V 3 mg of CaCO 3

Then 1000ml of boiled water sample = 20 / V 1 x V 3 / 20 * 1000mg of CaCO 3

= 1000 x V 3 / V 1 mg of CaCO 3

permanent hardness of boiled water sample = -----------------ppm

Temporary hardness of the given water sample = Total hardness ? Permanent hardness

= ------------------ppm

19







RESULT

(i) Total hardness of the given sample water = -------------- ppm.
(ii) Permanent hardness of the given sample water = --------------- ppm.
(iii) Temporary hardness of the given sample water = ----------------ppm.







VIVA-VOCE

1. Define ? Hard water
2. What is the structure of EDTA?
3. How will you calculate temporary hardness?
4. What is the role of the buffer in EDTA titration?
5. What is the permissible limit of hardness in drinking water?
6. Name the hardness producing ions present in water.
7. Name two salts which are responsible for temporary hardness.
8. Why is CaCO 3 taken as the standard?
9. Write the expansion of EDTA.
10. What is meant by EBT?











20





SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II
Standardisation of
AgNO 3
Estimation of Chloride
Burette solution

AgNO 3 solution

Std. AgNO 3 solution

Pipette solution

20ml std KCl solution

20 ml water sample

Indicator

1ml K 2CrO 4

1ml K 2CrO 4


End point

yellow to reddish brown

yellow to reddish brown

Titration I
Std. AgNO3 Vs KCl Indicator: Potassium Chromate













CALCULATION

Volume of KCl (V 1) = ------- ml

Strength of KCl (N 1) = ------- N

Volume of Silver Nitrate (V 2) = -------- ml

Strength of Siver Nitrate V 1N 1
N 2 =
V 1

= --------------------- N

S.No.
Volume of KCl
(ml)
Burette Reading (ml)
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

21




Expt.No. 3 ESTIMATION OF CHLORIDE CONTENT IN WATER
(ARGENTOMETRIC METHOD)
AIM
To estimate the amount of chloride present in given water sample by Argentometric method (Mohr?s
method). You are provided with standard solution of NaCl of strength --------N and a approximately N/10 solution of
Silver nitrate.

PRINCIPLE
The Chloride ion in the form of NaCl, KCl, CaCl 2, MgCl 2 etc., present in the water sample can be estimated
by Argentometric method or known as Mohr?s method. It is an example for precipitation titration. The reaction
between std. Sodium chloride and Silver nitrate is given below.
AgNO 3 + NaCl ? AgCl ? + NaNO 3
The completion of reaction can be observed by employing potassium chromate as the indicator. The end
point is the colour change from yellow to reddish brown due to the following reaction.
2AgNO 3 + K 2CrO 4 ? Ag 2CrO 4 ? + 2KNO 3
Potassium chromate indicator will not be precipitated as silver chromate until all the chlorides in the solution
have been precipitated as AgCl Since a precipitation reaction takes place in preference, this reaction takes place
only at the end point.

PROCEDURE
TITRATION I: STANDARDISATION OF SILVER NITRATE
Pipette out 20ml of standard sodium or potassium chloride solution into a clean conical flask. Add 1ml of 5%
K 2CrO 4 indicator, as the solution turns yellow in colour. Titrate it against silver nitrate solution taken in the burette.
Observe the nearness of the end point through the formation of coagulated silver chloride precipitate at the bottom
of the flask. Now add the silver nitrate drop by drop until the solution gets a faint reddish brown tinge. Repeat the
titration for concordant value. Let the volume of silver nitrate be V 2ml.





22






TITRATION - II

Std AgNO3 Vs WATER SAMPLE Indicator: Potassium Chromate













CALCULATION

Volume of Silver Nitrate (V 3) = ------------ ml

Strength of Siver Nitrate (N 3) = ------------- N

Volume of Water sample (V 4) = -------------- ml

Strength of Water sample V 3 N 3
(N 4) =
V 4

= ----------------- N

Amount of Chloride ion present in 1000 ml of the water sample = Equivalent mass of HCl X 1000


= N 4 x 35.46 x 1000


= -----------------mg/l







S.No.
Volume of water
sample (ml)
Burette Reading
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

23





TITRATION - II
ESTIMATION OF CHLORIDE ION

Pipette out 40 ml of the given water sample into a clean conical flask.To this sample add 1ml of 5% K 2CrO 4
indicator and titrate it against the standardized silver nitrate solution taken in the burette and continue the titration
until the solution produces a reddish brown colour. Note down the end point and repeat the titration for
concordance. Let the volume be V 3ml.







RESULT

The amount of chloride ion present in the water sample = ----------------- mg/l.




VIVA-VOCE

1. Why is this method known as Argentometric method?
2.
What is the chemical reaction between AgNO 3 and Cl
-
ions present in water?

3.
What is the form of Chloride ion present in water?

4. What is the reaction between AgNO 3 and K 2CrO 4 ?
5. What is the name of the method used in this titration?
6. Name the link solution used in the determination.
7. Name the solution used to standardize AgNO 3.
8. What is the indicator used in the determination?
9. How will you calculate the amount of chloride ion in the given solution?
10. What is the colour change in the titration?




24




SHORT PROCEDURE


CONTENTS

TITRATION I

TITRATION II
Burette solution

Std Sodium Hydroxide

Std Sodium Hydroxide

Pipette solution

20 ml hydrochloric acid 20 ml hydrochloric acid
Additional solution


20 ml distilled water

20 ml distilled water


End point



Sudden increase in pH
pH gradual increase

Equivalent Weight of HCl = 36.5







ROUGH GRAPH FAIR GRAPH











pH
? pH/ ? V





Volume of NaOH
(ml)
Volume of NaOH
(ml)





FirstRanker.com - FirstRanker's Choice



?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





3


PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)
1. Fundamentals
To provide students with a solid foundation in Mathematics, Science and fundamentals of engineering,
enabling them to apply, to find solutions for engineering problems and use this knowledge to acquire higher
education
2. Core Competence
To train the students in chemistry practicals so that they apply their knowledge and training to compare,
and to analyze various engineering industrial problems to find solutions
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice this enables
them to find solutions for the real time problems in industry, and to design products
4. Professionalism
To inculcate professional and effective communication skills, leadership qualities and team spirit in the
students to make them multi-faceted personalities and develop their ability to relate engineering issues to
broader social context
5. Lifelong Learning/Ethics
To demonstrate and practice ethical and professional responsibilities in the industry and society in the
large, through commitment and lifelong learning needed for successful professional career






4


PROGRAMME OUTCOMES (POs)
To demonstrate and apply knowledge of Mathematics, Science and engineering fundamentals in the following
experiments.
1 .To estimate HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. To determine total, temporary & permanent hardness of water by EDTA method.
3. To determine DO content of water sample by Winkler?s method.
4. To determine chloride content of water sample by Argentometric method.
5. To estimate copper content of the given solution by Iodometry.
6. To determine strength of given hydrochloric acid using pH meter.
7. To determine strength of acids in a mixture of acids using conductivity meter.
8. To determine iron content of the given solution using potentiometer.
9. To estimate iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. To estimate sodium and potassium present in water using flame photometer.
11. To determine molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. To determine Pseudo first order kinetics ? ester hydrolysis.
13. To determine Corrosion experiment ? weight loss method.
14. To estimate CMC.
15. To estimate Phase change in a solid.
16. To determine strength of strong acid vs strong base using conductivity meter.











5

BS8161 - CHEMISTRY LABORATORY
SYLLABUS


? To make the student to acquire practical skills in the determination of water quality
parameters through volumetric and instrumental analysis.

? ???? ??? ???? ?? ???? ? ? ?To acquaint the students with the determination of molecular weight of a polymer by
viscometery.

LIST OF EXPERIMENTS:
1. Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. Determination of total, temporary & permanent hardness of water by EDTA method.
3. Determination of DO content of water sample by Winkler?s method.
4. Determination of chloride content of water sample by Argentometric method.
5. Estimation of copper content of the given solution by Iodometry.
6. Determination of strength of given hydrochloric acid using pH meter.
7. Determination of strength of acids in a mixture of acids using conductivity meter.
8. Estimation of iron content of the given solution using potentiometer.
9. Estimation of iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. Estimation of sodium and potassium present in water using flame photometer.
11. Determination of molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. Pseudo first order kinetics ? ester hydrolysis.
13. Corrosion experiment ? weight loss method.
14. Determination of CMC.
15. Phase change in a solid.
16. Conductometric titration of strong acid vs strong base.




? The students will be outfitted with hands-on knowledge in the quantitative chemical
analysis of water quality related parameters.
COURSE OBJECTIVES
COURSE OUTCOMES
6


INDEX [ SEMESTER ? I ]


S.No.



Date


Experiment

Date of
submission



Mark


Signature

1.

Estimation of HCl using Na 2CO 3 as
primary standard and Determination of
alkalinity in water sample.



2.


Determination of total, temporary &
permanent hardness of water by EDTA
method.



3.


Determination of chloride content of water
sample by argentometric method.



4.


Determination of strength of given
hydrochloric acid using pH meter.



5.


Determination of strength of acids in a
mixture of acids using conductivity meter.



6.


Estimation of iron content of the given
solution using potentiometer.



7.





Conductometric titration of strong acid Vs
strong base.



8.



Estimation of copper content of the given
solution by Iodometry


9.
Estimation of sodium and potassium
present in water using flame photometer




7




CONTENTS


S.No.


NAME OF EXPERIMENT

PAGE
No.
SEMESTER - I
1.
Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in
water sample.
09
2. Determination of total, temporary & permanent hardness of water by EDTA method. 15
3. Determination of chloride content of water sample by Argentometric method. 21
4. Determination of strength of given hydrochloric acid using pH meter. 25
5. Determination of strength of acids in a mixture of acids using conductivity meter. 29
6. Estimation of iron content of the given solution using potentiometer. 33
7. Conductometric titration of strong acid Vs strong base.

39


42

8


Estimation of copper content of the given solution by Iodometry 43
9 Estimation of sodium and potassium present in water using flame photometer 47






8



SHORT PROCEDURE:

CONTENTS
TITRATION
Estimation of alkalinity in water sample
(Std HCl Vs water sample)

Burette solution

Std. HCl


Pipette solution

Water sample


Indicator


(i) Phenolphthalein
(ii) Methyl orange


End point

(i) Disappearance of pink colour
(ii) Appearance of reddish orange colour






Relationship
between P &M
Nature of alkalinity
Amount of individual
alkalinities
OH
-
HCO 3
-


CO 3
2-

P = M

only OH
-

P or M

?
0.0

0.0


2P = M

only CO 3
2-


2P or M


0.0


0.0


?

P =0, M?0

only HCO 3
-



M



0.0



?

0.0


2P > M


OH
-
&CO 3
2-


OH
-
= 2P-M
CO 3
2-
= 2(M-P)


?

0.0

?

P < ? M




HCO 3
-
&CO 3
2-


HCO 3
-
= M-2P
CO 3
2-
= 2P

0.0 ? ?




9





Expt. No. 1 DETERMINATION OF ALKALINITY IN WATER
AIM
To determine the type and amounts of alkalinity in the given water sample. A standard solution of Na 2CO 3
of strength ____N is given.

PRINCIPLE
Alkalinity in water is due to the presence of soluble hydroxides, bicarbonates and carbonates.
Determination of various types and amounts of alkalinity is easily carried out by titration with standard HCl
employing the indicators phenolphthalein and methyl orange independently or in succession.

The following reactions occur when different types of alkalinity are neutralized with acid.

OH
?
+ H
+
? H 2O completed at pH 8.2-9.0 ----- (1)

CO 3
2 ?
+ H
+
? HCO 3
?
----- (2)

HCO 3
?
+ H
+
? (H 2CO 3) ? H 2O + CO 2, completed at pH 4.2-5.5 ----- (3)

Neutralisation (1) & (2) will be notified by phenolphthalein end-point while all the three will be

accounted by
methyl orange end-point. Bicarbonate in eqn. (3) may be due to the existence of soluble free bicarbonate salts and
bicarbonates resulting from half neutralization of soluble carbonates (eqn. (2))

Various steps to be followed

a) A known volume of water sample is titrated against std. HCl using first phenolphthalein indicator till
end-point (P) and the titration is continued without break using methyl orange indicator till the end-
point (M).



10


Titration

Estimation of Alkalinity in water sample

Standard HCl Vs Water sample Indicator: 1. Phenolphthalein
2. Methyl Orange


S.No.
Volume
of water
sample (ml)
Burette Reading
Concordant value

Initial Phenolphthalein End
Point (P)
Methyl Orange End
Point (M)

1

2






CALCULATION

Hydroxide ion alkalinity
Volume of HCl (2P-M) = ???????ml

Strength of HCl = ???????? N

Volume of water sample = ???????...ml

Strength of water sample = Volume of HCl (2P-M) x Strength of HCl
Volume of water sample

=

? Hydroxide ion alkalinity in terms of
CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ??????.mg/l







11




b) From the magnitudes of the P & M, the nature of alkalinity can be arrived as follows:

(i) P = M => Presence of only OH
-

(ii) 2P = M => Presence of only CO 3
2-

(iii) P =0, M=0 => Presence of only HCO 3
-
(iv) 2P > M => Presence of OH
-
& CO 3
2-
(v) 2P < M => Presence of HCO 3
-
& CO 3
2-

(Mixture of OH
-
& HCO3
-
is not listed since they do not exist together and are considered equivalent to CO 3
2-
).

PROCEDURE
TITRATION
ESTIMATION OF ALKALINITY IN WATER SAMPLE

Exactly 20 ml of water sample is pipetted out into a clean conical flask. Few drops of phenolphthalein
indicator are added and titrated against a standardized HCl taken in the burette. The end point is the
disappearance of pink colour, which is noted as P. Few drops of methyl orange indicator is added to the same
solution. The solution turns to yellow. The titration is continued further by adding same HCl without break till the
end point is reached. The end point is the colour change from yellow to reddish orange.

The experiment is repeated to get concordant values. From the magnitudes of P & M values, the type of
alkalinity present in the water sample is inferred and the individual amounts are calculated and reported.










12


Carbonate ion alkalinity

Volume of HCl 2 (M ? P) = ??? ????????ml

Strength of HCl = ??.?????..???...N

Volume of water sample =........................................ml

Strength of water sample = Volume of HCl 2 (M ? P) x Strength of HCl
Volume of water sample

= ???????????.. N




? Carbonate ion alkalinity
in terms of CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ???????????mg/l

















13





RESULT

1) The type of alkalinity present in the water sample = -------------------------ions.

2) The individual amounts of alkalinity present in the water sample:
Hydroxide ion alkalinity

= ----------------- ppm
Carbonate ion alkalinity = ------------------ ppm
Bicarbonate ion alkalinity = ----------------- ppm





VIVA-VOCE


1. What is meant by alkalinity?
2. What are the ions responsible for alkalinity?
3. Why OH
-
and HCO 3
?
ions cannot exist together in water?
4. What are the ions responsible for alkalinity when 2P > M?
5. What is the pH range for both in acidic and basic solutions?
6. What is the colour of phenolphthalein in an acid and in an alkaline solution?
7. What is the purpose of using two indicators in same titration?
8. What are the possible combinations of ions for alkalinity?
9. How is the amount of alkalinity expressed?
10. What are the types of indicator used in this experiment?







14

SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II TITRATION III
Standardisation of
EDTA
(EDTA Vs Std
Hard water)
Determination of
total hardness
(Std EDTA Vs Hard
water sample)
Determination of
permanent hardness
(Std EDTA Vs Boiled
Hard water sample)

Burette solution

EDTA solution

EDTA solution

EDTA solution

Pipette solution

20ml Std. hard water

20 ml hard water sample

20ml boiled hard water sample

Indicator

2 drops of EBT

2 drops of EBT

2 drops of EBT

Additional soln.


Ammoniacal Buffer
solution (5ml)

Ammoniacal Buffer solution
(5ml)

Ammoniacal Buffer solution
(5ml)
End point Wine - red to Steel blue Wine - red to steel blue Wine - red to Steel blue




STANDARDISATION OF EDTA
Titration - I
Std. HARD WATER Vs EDTA Indicator: EBT

S. No.
Volume of std hard
water (ml)
Burette Reading Volume of
EDTA
(V 1) (ml)
Concordant value

Initial

Final



Volume of std .hard water taken = 20 ml
Volume of EDTA consumed (V 1) = --------------- ml
1 ml of std.hard water = 1mg of CaCO 3
20 ml of std hard water = 20 mg of CaCO 3

V 1 ml of EDTA solution containing 20 mg of CaCO 3
1 ml of EDTA solution = 20 / V 1 mg of CaCO 3
= -----------------------mg of CaCO 3


15

Expt. No. 2 DETERMINATION OF TOTAL, TEMPORARY AND
PERMANENT HARDNESS OF WATER

AIM
To estimate the amount of total, temporary & permanent hardness in the given sample of water.

PRINCIPLE
The estimation is based on the complexometric titration.

(i) Total hardness of water is estimated by titrating against EDTA using EBT indicator.
EBT+M ?[EBT-M] (unstable complex)
(EBT-M) (Unstable complex) +EDTA ? [EDTA-M] (stable complex) +EBT
EBT indicator forms wine- red colored complex with metal ions present in water. On addition of EDTA
metal ions preferably forms complexes with EDTA and steel blue EBT indicator is set free. Therefore
change of colour from wine- red to steel blue denotes the end point.

(ii) Temporary hardness is removed by boiling the water.
Ca (HCO 3) 2 ? CaCO 3 +CO 2 ?+H 2O
Mg (HCO 3) 2 ? Mg(OH) 2 +2CO 2 ?
The precipitate is filtered and the remaining permanent hardness is estimated using EDTA.

PROCEDURE

TITRATION ? I
STANDARDISATION OF EDTA

Pipette out 20ml of standard hard water into a 250ml conical flask. Add 5ml of buffer solution and 3
drops of eriochrome black T indictor. Titrate the solution with EDTA from the burette until the colour
changes from wine- red to steel blue at the end point. Repeat the titration for concordant values. Let the
titre value be V 1ml.


16


Titration-II
SAMPLE HARD WATER Vs Std EDTA Indicator: EBT

S.No. Volume of sample
hard water (ml)
Burette Reading Volume of
EDTA
(V 2) (ml)
Concordant value

Initial

Final




CALCULATION

Calculation of total hardness


Volume of EDTA consumed (V 2) = ------------------------- ml
1ml of EDTA = 20 / V 1 mg of CaCO 3
V 2 ml of EDTA = 20 / V 1 x V 2 mg of CaCO 3

( i.e), If 20ml of sample hard water contains 20 x V 2 mg of CaCO 3 / V 1

Then 1000ml of water sample = 20 x V 2 x 1000 / V 1 x 20 mg of CaCO 3

= 1000 x V 2 / V 1 mg of CaCO3

Total hardness of given water sample = ---------------------ppm









17



DETERMINATION OF TOTAL HARDNESS

Pipette out 20ml of sample hard water into a clean conical flask. Add 5ml of buffer solution and 4 -5
drops of Eriochrome black -T indicator. Titrate the wine - red coloured solution with EDTA from the burette until
the colour steel blue appears at the end point. Repeat the titration for concordant values. Let the titre value be
V 2ml.



DETERMINATION OF PERMANENT HARDNESS

Take 100ml of hard water sample in a 500ml beaker and boil gently for about 1hour. Cool, filter it into a
100ml standard flask and make the volume up to the mark. Take 20ml of this solution and proceed it in the same
way as in titration (I). The volume of EDTA consumed corresponds to the permanent hardness of the water
sample. Let the titre value be V 3ml. Temporary hardness is calculated by subtracting permanent hardness from
total hardness.





















18




DETERMINATION OF PERMANENT HARDNESS
BOILED SAMPLE WATER Vs Std. EDTA Indicator: EBT


S.No.
Volume of boiled
hard water (ml)
Burette Reading (ml) Volume of
EDTA
(ml)

Concordant value

Initial Final



CALCULATION OF PERMANENT HARDNESS


Volume of EDTA consumed V 3 = ---------------------ml

1ml of EDTA = 20 / V 1 mg of CaCO 3

V 3ml of EDTA = 20 / V 1 x V 3 mg of CaCO 3

(i.e) 20 ml of boiled sample hard water = 20 / V 1 x V 3 mg of CaCO 3

Then 1000ml of boiled water sample = 20 / V 1 x V 3 / 20 * 1000mg of CaCO 3

= 1000 x V 3 / V 1 mg of CaCO 3

permanent hardness of boiled water sample = -----------------ppm

Temporary hardness of the given water sample = Total hardness ? Permanent hardness

= ------------------ppm

19







RESULT

(i) Total hardness of the given sample water = -------------- ppm.
(ii) Permanent hardness of the given sample water = --------------- ppm.
(iii) Temporary hardness of the given sample water = ----------------ppm.







VIVA-VOCE

1. Define ? Hard water
2. What is the structure of EDTA?
3. How will you calculate temporary hardness?
4. What is the role of the buffer in EDTA titration?
5. What is the permissible limit of hardness in drinking water?
6. Name the hardness producing ions present in water.
7. Name two salts which are responsible for temporary hardness.
8. Why is CaCO 3 taken as the standard?
9. Write the expansion of EDTA.
10. What is meant by EBT?











20





SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II
Standardisation of
AgNO 3
Estimation of Chloride
Burette solution

AgNO 3 solution

Std. AgNO 3 solution

Pipette solution

20ml std KCl solution

20 ml water sample

Indicator

1ml K 2CrO 4

1ml K 2CrO 4


End point

yellow to reddish brown

yellow to reddish brown

Titration I
Std. AgNO3 Vs KCl Indicator: Potassium Chromate













CALCULATION

Volume of KCl (V 1) = ------- ml

Strength of KCl (N 1) = ------- N

Volume of Silver Nitrate (V 2) = -------- ml

Strength of Siver Nitrate V 1N 1
N 2 =
V 1

= --------------------- N

S.No.
Volume of KCl
(ml)
Burette Reading (ml)
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

21




Expt.No. 3 ESTIMATION OF CHLORIDE CONTENT IN WATER
(ARGENTOMETRIC METHOD)
AIM
To estimate the amount of chloride present in given water sample by Argentometric method (Mohr?s
method). You are provided with standard solution of NaCl of strength --------N and a approximately N/10 solution of
Silver nitrate.

PRINCIPLE
The Chloride ion in the form of NaCl, KCl, CaCl 2, MgCl 2 etc., present in the water sample can be estimated
by Argentometric method or known as Mohr?s method. It is an example for precipitation titration. The reaction
between std. Sodium chloride and Silver nitrate is given below.
AgNO 3 + NaCl ? AgCl ? + NaNO 3
The completion of reaction can be observed by employing potassium chromate as the indicator. The end
point is the colour change from yellow to reddish brown due to the following reaction.
2AgNO 3 + K 2CrO 4 ? Ag 2CrO 4 ? + 2KNO 3
Potassium chromate indicator will not be precipitated as silver chromate until all the chlorides in the solution
have been precipitated as AgCl Since a precipitation reaction takes place in preference, this reaction takes place
only at the end point.

PROCEDURE
TITRATION I: STANDARDISATION OF SILVER NITRATE
Pipette out 20ml of standard sodium or potassium chloride solution into a clean conical flask. Add 1ml of 5%
K 2CrO 4 indicator, as the solution turns yellow in colour. Titrate it against silver nitrate solution taken in the burette.
Observe the nearness of the end point through the formation of coagulated silver chloride precipitate at the bottom
of the flask. Now add the silver nitrate drop by drop until the solution gets a faint reddish brown tinge. Repeat the
titration for concordant value. Let the volume of silver nitrate be V 2ml.





22






TITRATION - II

Std AgNO3 Vs WATER SAMPLE Indicator: Potassium Chromate













CALCULATION

Volume of Silver Nitrate (V 3) = ------------ ml

Strength of Siver Nitrate (N 3) = ------------- N

Volume of Water sample (V 4) = -------------- ml

Strength of Water sample V 3 N 3
(N 4) =
V 4

= ----------------- N

Amount of Chloride ion present in 1000 ml of the water sample = Equivalent mass of HCl X 1000


= N 4 x 35.46 x 1000


= -----------------mg/l







S.No.
Volume of water
sample (ml)
Burette Reading
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

23





TITRATION - II
ESTIMATION OF CHLORIDE ION

Pipette out 40 ml of the given water sample into a clean conical flask.To this sample add 1ml of 5% K 2CrO 4
indicator and titrate it against the standardized silver nitrate solution taken in the burette and continue the titration
until the solution produces a reddish brown colour. Note down the end point and repeat the titration for
concordance. Let the volume be V 3ml.







RESULT

The amount of chloride ion present in the water sample = ----------------- mg/l.




VIVA-VOCE

1. Why is this method known as Argentometric method?
2.
What is the chemical reaction between AgNO 3 and Cl
-
ions present in water?

3.
What is the form of Chloride ion present in water?

4. What is the reaction between AgNO 3 and K 2CrO 4 ?
5. What is the name of the method used in this titration?
6. Name the link solution used in the determination.
7. Name the solution used to standardize AgNO 3.
8. What is the indicator used in the determination?
9. How will you calculate the amount of chloride ion in the given solution?
10. What is the colour change in the titration?




24




SHORT PROCEDURE


CONTENTS

TITRATION I

TITRATION II
Burette solution

Std Sodium Hydroxide

Std Sodium Hydroxide

Pipette solution

20 ml hydrochloric acid 20 ml hydrochloric acid
Additional solution


20 ml distilled water

20 ml distilled water


End point



Sudden increase in pH
pH gradual increase

Equivalent Weight of HCl = 36.5







ROUGH GRAPH FAIR GRAPH











pH
? pH/ ? V





Volume of NaOH
(ml)
Volume of NaOH
(ml)





25



Expt. No. 4 DETERMINATION OF STRENGTH OF HCl by pH METRY

AIM
To determine the strength of given HCl by pH metry. A standard solution of 0.1N NaOH is provided.

PRINCIPLE
The pH of a solution is related to H
+
ion concentration by the following formula.

. pH = -log [ H
+
]

pH of a solution is indirectly related to H
+
ion concentration. When NaOH is added slowly to HCl, H
+
ions
get neutralized by OH
-
ions. The pH increases slowly.

H
+
+ Cl
-
+ Na
+
+ OH
-
? Na
+
+ Cl
-
+H 2O

When all H
+
ions of HCl are neutralized at the end point, addition of NaOH causes high increase in pH
because of the addition of excess OH
-
ions.

MATERIALS REQUIRED
pH meter, Glass electrode, Burette, Pipette, Std.NaOH, approximately N/10 HCl .

PROCEDURE

The burette is washed with distilled water, rinsed with the given std. Sodium hydroxide and filled with the
same solution. Exactly 10ml of the given HCl solution is pipetted out into a clean beaker. It is then diluted to 50ml
with distilled water. A glass electrode is dipped into the solution and its terminals are connected to a pH meter.

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?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





3


PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)
1. Fundamentals
To provide students with a solid foundation in Mathematics, Science and fundamentals of engineering,
enabling them to apply, to find solutions for engineering problems and use this knowledge to acquire higher
education
2. Core Competence
To train the students in chemistry practicals so that they apply their knowledge and training to compare,
and to analyze various engineering industrial problems to find solutions
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice this enables
them to find solutions for the real time problems in industry, and to design products
4. Professionalism
To inculcate professional and effective communication skills, leadership qualities and team spirit in the
students to make them multi-faceted personalities and develop their ability to relate engineering issues to
broader social context
5. Lifelong Learning/Ethics
To demonstrate and practice ethical and professional responsibilities in the industry and society in the
large, through commitment and lifelong learning needed for successful professional career






4


PROGRAMME OUTCOMES (POs)
To demonstrate and apply knowledge of Mathematics, Science and engineering fundamentals in the following
experiments.
1 .To estimate HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. To determine total, temporary & permanent hardness of water by EDTA method.
3. To determine DO content of water sample by Winkler?s method.
4. To determine chloride content of water sample by Argentometric method.
5. To estimate copper content of the given solution by Iodometry.
6. To determine strength of given hydrochloric acid using pH meter.
7. To determine strength of acids in a mixture of acids using conductivity meter.
8. To determine iron content of the given solution using potentiometer.
9. To estimate iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. To estimate sodium and potassium present in water using flame photometer.
11. To determine molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. To determine Pseudo first order kinetics ? ester hydrolysis.
13. To determine Corrosion experiment ? weight loss method.
14. To estimate CMC.
15. To estimate Phase change in a solid.
16. To determine strength of strong acid vs strong base using conductivity meter.











5

BS8161 - CHEMISTRY LABORATORY
SYLLABUS


? To make the student to acquire practical skills in the determination of water quality
parameters through volumetric and instrumental analysis.

? ???? ??? ???? ?? ???? ? ? ?To acquaint the students with the determination of molecular weight of a polymer by
viscometery.

LIST OF EXPERIMENTS:
1. Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. Determination of total, temporary & permanent hardness of water by EDTA method.
3. Determination of DO content of water sample by Winkler?s method.
4. Determination of chloride content of water sample by Argentometric method.
5. Estimation of copper content of the given solution by Iodometry.
6. Determination of strength of given hydrochloric acid using pH meter.
7. Determination of strength of acids in a mixture of acids using conductivity meter.
8. Estimation of iron content of the given solution using potentiometer.
9. Estimation of iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. Estimation of sodium and potassium present in water using flame photometer.
11. Determination of molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. Pseudo first order kinetics ? ester hydrolysis.
13. Corrosion experiment ? weight loss method.
14. Determination of CMC.
15. Phase change in a solid.
16. Conductometric titration of strong acid vs strong base.




? The students will be outfitted with hands-on knowledge in the quantitative chemical
analysis of water quality related parameters.
COURSE OBJECTIVES
COURSE OUTCOMES
6


INDEX [ SEMESTER ? I ]


S.No.



Date


Experiment

Date of
submission



Mark


Signature

1.

Estimation of HCl using Na 2CO 3 as
primary standard and Determination of
alkalinity in water sample.



2.


Determination of total, temporary &
permanent hardness of water by EDTA
method.



3.


Determination of chloride content of water
sample by argentometric method.



4.


Determination of strength of given
hydrochloric acid using pH meter.



5.


Determination of strength of acids in a
mixture of acids using conductivity meter.



6.


Estimation of iron content of the given
solution using potentiometer.



7.





Conductometric titration of strong acid Vs
strong base.



8.



Estimation of copper content of the given
solution by Iodometry


9.
Estimation of sodium and potassium
present in water using flame photometer




7




CONTENTS


S.No.


NAME OF EXPERIMENT

PAGE
No.
SEMESTER - I
1.
Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in
water sample.
09
2. Determination of total, temporary & permanent hardness of water by EDTA method. 15
3. Determination of chloride content of water sample by Argentometric method. 21
4. Determination of strength of given hydrochloric acid using pH meter. 25
5. Determination of strength of acids in a mixture of acids using conductivity meter. 29
6. Estimation of iron content of the given solution using potentiometer. 33
7. Conductometric titration of strong acid Vs strong base.

39


42

8


Estimation of copper content of the given solution by Iodometry 43
9 Estimation of sodium and potassium present in water using flame photometer 47






8



SHORT PROCEDURE:

CONTENTS
TITRATION
Estimation of alkalinity in water sample
(Std HCl Vs water sample)

Burette solution

Std. HCl


Pipette solution

Water sample


Indicator


(i) Phenolphthalein
(ii) Methyl orange


End point

(i) Disappearance of pink colour
(ii) Appearance of reddish orange colour






Relationship
between P &M
Nature of alkalinity
Amount of individual
alkalinities
OH
-
HCO 3
-


CO 3
2-

P = M

only OH
-

P or M

?
0.0

0.0


2P = M

only CO 3
2-


2P or M


0.0


0.0


?

P =0, M?0

only HCO 3
-



M



0.0



?

0.0


2P > M


OH
-
&CO 3
2-


OH
-
= 2P-M
CO 3
2-
= 2(M-P)


?

0.0

?

P < ? M




HCO 3
-
&CO 3
2-


HCO 3
-
= M-2P
CO 3
2-
= 2P

0.0 ? ?




9





Expt. No. 1 DETERMINATION OF ALKALINITY IN WATER
AIM
To determine the type and amounts of alkalinity in the given water sample. A standard solution of Na 2CO 3
of strength ____N is given.

PRINCIPLE
Alkalinity in water is due to the presence of soluble hydroxides, bicarbonates and carbonates.
Determination of various types and amounts of alkalinity is easily carried out by titration with standard HCl
employing the indicators phenolphthalein and methyl orange independently or in succession.

The following reactions occur when different types of alkalinity are neutralized with acid.

OH
?
+ H
+
? H 2O completed at pH 8.2-9.0 ----- (1)

CO 3
2 ?
+ H
+
? HCO 3
?
----- (2)

HCO 3
?
+ H
+
? (H 2CO 3) ? H 2O + CO 2, completed at pH 4.2-5.5 ----- (3)

Neutralisation (1) & (2) will be notified by phenolphthalein end-point while all the three will be

accounted by
methyl orange end-point. Bicarbonate in eqn. (3) may be due to the existence of soluble free bicarbonate salts and
bicarbonates resulting from half neutralization of soluble carbonates (eqn. (2))

Various steps to be followed

a) A known volume of water sample is titrated against std. HCl using first phenolphthalein indicator till
end-point (P) and the titration is continued without break using methyl orange indicator till the end-
point (M).



10


Titration

Estimation of Alkalinity in water sample

Standard HCl Vs Water sample Indicator: 1. Phenolphthalein
2. Methyl Orange


S.No.
Volume
of water
sample (ml)
Burette Reading
Concordant value

Initial Phenolphthalein End
Point (P)
Methyl Orange End
Point (M)

1

2






CALCULATION

Hydroxide ion alkalinity
Volume of HCl (2P-M) = ???????ml

Strength of HCl = ???????? N

Volume of water sample = ???????...ml

Strength of water sample = Volume of HCl (2P-M) x Strength of HCl
Volume of water sample

=

? Hydroxide ion alkalinity in terms of
CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ??????.mg/l







11




b) From the magnitudes of the P & M, the nature of alkalinity can be arrived as follows:

(i) P = M => Presence of only OH
-

(ii) 2P = M => Presence of only CO 3
2-

(iii) P =0, M=0 => Presence of only HCO 3
-
(iv) 2P > M => Presence of OH
-
& CO 3
2-
(v) 2P < M => Presence of HCO 3
-
& CO 3
2-

(Mixture of OH
-
& HCO3
-
is not listed since they do not exist together and are considered equivalent to CO 3
2-
).

PROCEDURE
TITRATION
ESTIMATION OF ALKALINITY IN WATER SAMPLE

Exactly 20 ml of water sample is pipetted out into a clean conical flask. Few drops of phenolphthalein
indicator are added and titrated against a standardized HCl taken in the burette. The end point is the
disappearance of pink colour, which is noted as P. Few drops of methyl orange indicator is added to the same
solution. The solution turns to yellow. The titration is continued further by adding same HCl without break till the
end point is reached. The end point is the colour change from yellow to reddish orange.

The experiment is repeated to get concordant values. From the magnitudes of P & M values, the type of
alkalinity present in the water sample is inferred and the individual amounts are calculated and reported.










12


Carbonate ion alkalinity

Volume of HCl 2 (M ? P) = ??? ????????ml

Strength of HCl = ??.?????..???...N

Volume of water sample =........................................ml

Strength of water sample = Volume of HCl 2 (M ? P) x Strength of HCl
Volume of water sample

= ???????????.. N




? Carbonate ion alkalinity
in terms of CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ???????????mg/l

















13





RESULT

1) The type of alkalinity present in the water sample = -------------------------ions.

2) The individual amounts of alkalinity present in the water sample:
Hydroxide ion alkalinity

= ----------------- ppm
Carbonate ion alkalinity = ------------------ ppm
Bicarbonate ion alkalinity = ----------------- ppm





VIVA-VOCE


1. What is meant by alkalinity?
2. What are the ions responsible for alkalinity?
3. Why OH
-
and HCO 3
?
ions cannot exist together in water?
4. What are the ions responsible for alkalinity when 2P > M?
5. What is the pH range for both in acidic and basic solutions?
6. What is the colour of phenolphthalein in an acid and in an alkaline solution?
7. What is the purpose of using two indicators in same titration?
8. What are the possible combinations of ions for alkalinity?
9. How is the amount of alkalinity expressed?
10. What are the types of indicator used in this experiment?







14

SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II TITRATION III
Standardisation of
EDTA
(EDTA Vs Std
Hard water)
Determination of
total hardness
(Std EDTA Vs Hard
water sample)
Determination of
permanent hardness
(Std EDTA Vs Boiled
Hard water sample)

Burette solution

EDTA solution

EDTA solution

EDTA solution

Pipette solution

20ml Std. hard water

20 ml hard water sample

20ml boiled hard water sample

Indicator

2 drops of EBT

2 drops of EBT

2 drops of EBT

Additional soln.


Ammoniacal Buffer
solution (5ml)

Ammoniacal Buffer solution
(5ml)

Ammoniacal Buffer solution
(5ml)
End point Wine - red to Steel blue Wine - red to steel blue Wine - red to Steel blue




STANDARDISATION OF EDTA
Titration - I
Std. HARD WATER Vs EDTA Indicator: EBT

S. No.
Volume of std hard
water (ml)
Burette Reading Volume of
EDTA
(V 1) (ml)
Concordant value

Initial

Final



Volume of std .hard water taken = 20 ml
Volume of EDTA consumed (V 1) = --------------- ml
1 ml of std.hard water = 1mg of CaCO 3
20 ml of std hard water = 20 mg of CaCO 3

V 1 ml of EDTA solution containing 20 mg of CaCO 3
1 ml of EDTA solution = 20 / V 1 mg of CaCO 3
= -----------------------mg of CaCO 3


15

Expt. No. 2 DETERMINATION OF TOTAL, TEMPORARY AND
PERMANENT HARDNESS OF WATER

AIM
To estimate the amount of total, temporary & permanent hardness in the given sample of water.

PRINCIPLE
The estimation is based on the complexometric titration.

(i) Total hardness of water is estimated by titrating against EDTA using EBT indicator.
EBT+M ?[EBT-M] (unstable complex)
(EBT-M) (Unstable complex) +EDTA ? [EDTA-M] (stable complex) +EBT
EBT indicator forms wine- red colored complex with metal ions present in water. On addition of EDTA
metal ions preferably forms complexes with EDTA and steel blue EBT indicator is set free. Therefore
change of colour from wine- red to steel blue denotes the end point.

(ii) Temporary hardness is removed by boiling the water.
Ca (HCO 3) 2 ? CaCO 3 +CO 2 ?+H 2O
Mg (HCO 3) 2 ? Mg(OH) 2 +2CO 2 ?
The precipitate is filtered and the remaining permanent hardness is estimated using EDTA.

PROCEDURE

TITRATION ? I
STANDARDISATION OF EDTA

Pipette out 20ml of standard hard water into a 250ml conical flask. Add 5ml of buffer solution and 3
drops of eriochrome black T indictor. Titrate the solution with EDTA from the burette until the colour
changes from wine- red to steel blue at the end point. Repeat the titration for concordant values. Let the
titre value be V 1ml.


16


Titration-II
SAMPLE HARD WATER Vs Std EDTA Indicator: EBT

S.No. Volume of sample
hard water (ml)
Burette Reading Volume of
EDTA
(V 2) (ml)
Concordant value

Initial

Final




CALCULATION

Calculation of total hardness


Volume of EDTA consumed (V 2) = ------------------------- ml
1ml of EDTA = 20 / V 1 mg of CaCO 3
V 2 ml of EDTA = 20 / V 1 x V 2 mg of CaCO 3

( i.e), If 20ml of sample hard water contains 20 x V 2 mg of CaCO 3 / V 1

Then 1000ml of water sample = 20 x V 2 x 1000 / V 1 x 20 mg of CaCO 3

= 1000 x V 2 / V 1 mg of CaCO3

Total hardness of given water sample = ---------------------ppm









17



DETERMINATION OF TOTAL HARDNESS

Pipette out 20ml of sample hard water into a clean conical flask. Add 5ml of buffer solution and 4 -5
drops of Eriochrome black -T indicator. Titrate the wine - red coloured solution with EDTA from the burette until
the colour steel blue appears at the end point. Repeat the titration for concordant values. Let the titre value be
V 2ml.



DETERMINATION OF PERMANENT HARDNESS

Take 100ml of hard water sample in a 500ml beaker and boil gently for about 1hour. Cool, filter it into a
100ml standard flask and make the volume up to the mark. Take 20ml of this solution and proceed it in the same
way as in titration (I). The volume of EDTA consumed corresponds to the permanent hardness of the water
sample. Let the titre value be V 3ml. Temporary hardness is calculated by subtracting permanent hardness from
total hardness.





















18




DETERMINATION OF PERMANENT HARDNESS
BOILED SAMPLE WATER Vs Std. EDTA Indicator: EBT


S.No.
Volume of boiled
hard water (ml)
Burette Reading (ml) Volume of
EDTA
(ml)

Concordant value

Initial Final



CALCULATION OF PERMANENT HARDNESS


Volume of EDTA consumed V 3 = ---------------------ml

1ml of EDTA = 20 / V 1 mg of CaCO 3

V 3ml of EDTA = 20 / V 1 x V 3 mg of CaCO 3

(i.e) 20 ml of boiled sample hard water = 20 / V 1 x V 3 mg of CaCO 3

Then 1000ml of boiled water sample = 20 / V 1 x V 3 / 20 * 1000mg of CaCO 3

= 1000 x V 3 / V 1 mg of CaCO 3

permanent hardness of boiled water sample = -----------------ppm

Temporary hardness of the given water sample = Total hardness ? Permanent hardness

= ------------------ppm

19







RESULT

(i) Total hardness of the given sample water = -------------- ppm.
(ii) Permanent hardness of the given sample water = --------------- ppm.
(iii) Temporary hardness of the given sample water = ----------------ppm.







VIVA-VOCE

1. Define ? Hard water
2. What is the structure of EDTA?
3. How will you calculate temporary hardness?
4. What is the role of the buffer in EDTA titration?
5. What is the permissible limit of hardness in drinking water?
6. Name the hardness producing ions present in water.
7. Name two salts which are responsible for temporary hardness.
8. Why is CaCO 3 taken as the standard?
9. Write the expansion of EDTA.
10. What is meant by EBT?











20





SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II
Standardisation of
AgNO 3
Estimation of Chloride
Burette solution

AgNO 3 solution

Std. AgNO 3 solution

Pipette solution

20ml std KCl solution

20 ml water sample

Indicator

1ml K 2CrO 4

1ml K 2CrO 4


End point

yellow to reddish brown

yellow to reddish brown

Titration I
Std. AgNO3 Vs KCl Indicator: Potassium Chromate













CALCULATION

Volume of KCl (V 1) = ------- ml

Strength of KCl (N 1) = ------- N

Volume of Silver Nitrate (V 2) = -------- ml

Strength of Siver Nitrate V 1N 1
N 2 =
V 1

= --------------------- N

S.No.
Volume of KCl
(ml)
Burette Reading (ml)
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

21




Expt.No. 3 ESTIMATION OF CHLORIDE CONTENT IN WATER
(ARGENTOMETRIC METHOD)
AIM
To estimate the amount of chloride present in given water sample by Argentometric method (Mohr?s
method). You are provided with standard solution of NaCl of strength --------N and a approximately N/10 solution of
Silver nitrate.

PRINCIPLE
The Chloride ion in the form of NaCl, KCl, CaCl 2, MgCl 2 etc., present in the water sample can be estimated
by Argentometric method or known as Mohr?s method. It is an example for precipitation titration. The reaction
between std. Sodium chloride and Silver nitrate is given below.
AgNO 3 + NaCl ? AgCl ? + NaNO 3
The completion of reaction can be observed by employing potassium chromate as the indicator. The end
point is the colour change from yellow to reddish brown due to the following reaction.
2AgNO 3 + K 2CrO 4 ? Ag 2CrO 4 ? + 2KNO 3
Potassium chromate indicator will not be precipitated as silver chromate until all the chlorides in the solution
have been precipitated as AgCl Since a precipitation reaction takes place in preference, this reaction takes place
only at the end point.

PROCEDURE
TITRATION I: STANDARDISATION OF SILVER NITRATE
Pipette out 20ml of standard sodium or potassium chloride solution into a clean conical flask. Add 1ml of 5%
K 2CrO 4 indicator, as the solution turns yellow in colour. Titrate it against silver nitrate solution taken in the burette.
Observe the nearness of the end point through the formation of coagulated silver chloride precipitate at the bottom
of the flask. Now add the silver nitrate drop by drop until the solution gets a faint reddish brown tinge. Repeat the
titration for concordant value. Let the volume of silver nitrate be V 2ml.





22






TITRATION - II

Std AgNO3 Vs WATER SAMPLE Indicator: Potassium Chromate













CALCULATION

Volume of Silver Nitrate (V 3) = ------------ ml

Strength of Siver Nitrate (N 3) = ------------- N

Volume of Water sample (V 4) = -------------- ml

Strength of Water sample V 3 N 3
(N 4) =
V 4

= ----------------- N

Amount of Chloride ion present in 1000 ml of the water sample = Equivalent mass of HCl X 1000


= N 4 x 35.46 x 1000


= -----------------mg/l







S.No.
Volume of water
sample (ml)
Burette Reading
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

23





TITRATION - II
ESTIMATION OF CHLORIDE ION

Pipette out 40 ml of the given water sample into a clean conical flask.To this sample add 1ml of 5% K 2CrO 4
indicator and titrate it against the standardized silver nitrate solution taken in the burette and continue the titration
until the solution produces a reddish brown colour. Note down the end point and repeat the titration for
concordance. Let the volume be V 3ml.







RESULT

The amount of chloride ion present in the water sample = ----------------- mg/l.




VIVA-VOCE

1. Why is this method known as Argentometric method?
2.
What is the chemical reaction between AgNO 3 and Cl
-
ions present in water?

3.
What is the form of Chloride ion present in water?

4. What is the reaction between AgNO 3 and K 2CrO 4 ?
5. What is the name of the method used in this titration?
6. Name the link solution used in the determination.
7. Name the solution used to standardize AgNO 3.
8. What is the indicator used in the determination?
9. How will you calculate the amount of chloride ion in the given solution?
10. What is the colour change in the titration?




24




SHORT PROCEDURE


CONTENTS

TITRATION I

TITRATION II
Burette solution

Std Sodium Hydroxide

Std Sodium Hydroxide

Pipette solution

20 ml hydrochloric acid 20 ml hydrochloric acid
Additional solution


20 ml distilled water

20 ml distilled water


End point



Sudden increase in pH
pH gradual increase

Equivalent Weight of HCl = 36.5







ROUGH GRAPH FAIR GRAPH











pH
? pH/ ? V





Volume of NaOH
(ml)
Volume of NaOH
(ml)





25



Expt. No. 4 DETERMINATION OF STRENGTH OF HCl by pH METRY

AIM
To determine the strength of given HCl by pH metry. A standard solution of 0.1N NaOH is provided.

PRINCIPLE
The pH of a solution is related to H
+
ion concentration by the following formula.

. pH = -log [ H
+
]

pH of a solution is indirectly related to H
+
ion concentration. When NaOH is added slowly to HCl, H
+
ions
get neutralized by OH
-
ions. The pH increases slowly.

H
+
+ Cl
-
+ Na
+
+ OH
-
? Na
+
+ Cl
-
+H 2O

When all H
+
ions of HCl are neutralized at the end point, addition of NaOH causes high increase in pH
because of the addition of excess OH
-
ions.

MATERIALS REQUIRED
pH meter, Glass electrode, Burette, Pipette, Std.NaOH, approximately N/10 HCl .

PROCEDURE

The burette is washed with distilled water, rinsed with the given std. Sodium hydroxide and filled with the
same solution. Exactly 10ml of the given HCl solution is pipetted out into a clean beaker. It is then diluted to 50ml
with distilled water. A glass electrode is dipped into the solution and its terminals are connected to a pH meter.

26

TITRATION - I
S.No Volume of
NaOH (ml)
pH
1

2

3

4

5

6

7

8

9

10


TITRATION - II



CALCULATION

Volume of NaOH (V 1) = ------------------- ml ( titre value)
Strength of NaOH (N 1) = ------------------- N
Volume of HCl (V 2) = ------------------ml
Strength of HCl (N 2) = ------------------ N
N 2 = V 1 N 1 / V 2
Strength of HCl = -------------------- N
Amount of HCl present in 1000ml of the given solution = Strength x equivalent weight of HCl
= ------------------ X 36.5
= --------------------- g
S.No Volume of
NaOH (ml)
pH
11

12

13

14

15

16

17

18

19

20

S.No
Volume of
NaOH (ml)
pH ?pH ?V ?pH / ?V
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
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?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





3


PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)
1. Fundamentals
To provide students with a solid foundation in Mathematics, Science and fundamentals of engineering,
enabling them to apply, to find solutions for engineering problems and use this knowledge to acquire higher
education
2. Core Competence
To train the students in chemistry practicals so that they apply their knowledge and training to compare,
and to analyze various engineering industrial problems to find solutions
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice this enables
them to find solutions for the real time problems in industry, and to design products
4. Professionalism
To inculcate professional and effective communication skills, leadership qualities and team spirit in the
students to make them multi-faceted personalities and develop their ability to relate engineering issues to
broader social context
5. Lifelong Learning/Ethics
To demonstrate and practice ethical and professional responsibilities in the industry and society in the
large, through commitment and lifelong learning needed for successful professional career






4


PROGRAMME OUTCOMES (POs)
To demonstrate and apply knowledge of Mathematics, Science and engineering fundamentals in the following
experiments.
1 .To estimate HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. To determine total, temporary & permanent hardness of water by EDTA method.
3. To determine DO content of water sample by Winkler?s method.
4. To determine chloride content of water sample by Argentometric method.
5. To estimate copper content of the given solution by Iodometry.
6. To determine strength of given hydrochloric acid using pH meter.
7. To determine strength of acids in a mixture of acids using conductivity meter.
8. To determine iron content of the given solution using potentiometer.
9. To estimate iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. To estimate sodium and potassium present in water using flame photometer.
11. To determine molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. To determine Pseudo first order kinetics ? ester hydrolysis.
13. To determine Corrosion experiment ? weight loss method.
14. To estimate CMC.
15. To estimate Phase change in a solid.
16. To determine strength of strong acid vs strong base using conductivity meter.











5

BS8161 - CHEMISTRY LABORATORY
SYLLABUS


? To make the student to acquire practical skills in the determination of water quality
parameters through volumetric and instrumental analysis.

? ???? ??? ???? ?? ???? ? ? ?To acquaint the students with the determination of molecular weight of a polymer by
viscometery.

LIST OF EXPERIMENTS:
1. Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. Determination of total, temporary & permanent hardness of water by EDTA method.
3. Determination of DO content of water sample by Winkler?s method.
4. Determination of chloride content of water sample by Argentometric method.
5. Estimation of copper content of the given solution by Iodometry.
6. Determination of strength of given hydrochloric acid using pH meter.
7. Determination of strength of acids in a mixture of acids using conductivity meter.
8. Estimation of iron content of the given solution using potentiometer.
9. Estimation of iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. Estimation of sodium and potassium present in water using flame photometer.
11. Determination of molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. Pseudo first order kinetics ? ester hydrolysis.
13. Corrosion experiment ? weight loss method.
14. Determination of CMC.
15. Phase change in a solid.
16. Conductometric titration of strong acid vs strong base.




? The students will be outfitted with hands-on knowledge in the quantitative chemical
analysis of water quality related parameters.
COURSE OBJECTIVES
COURSE OUTCOMES
6


INDEX [ SEMESTER ? I ]


S.No.



Date


Experiment

Date of
submission



Mark


Signature

1.

Estimation of HCl using Na 2CO 3 as
primary standard and Determination of
alkalinity in water sample.



2.


Determination of total, temporary &
permanent hardness of water by EDTA
method.



3.


Determination of chloride content of water
sample by argentometric method.



4.


Determination of strength of given
hydrochloric acid using pH meter.



5.


Determination of strength of acids in a
mixture of acids using conductivity meter.



6.


Estimation of iron content of the given
solution using potentiometer.



7.





Conductometric titration of strong acid Vs
strong base.



8.



Estimation of copper content of the given
solution by Iodometry


9.
Estimation of sodium and potassium
present in water using flame photometer




7




CONTENTS


S.No.


NAME OF EXPERIMENT

PAGE
No.
SEMESTER - I
1.
Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in
water sample.
09
2. Determination of total, temporary & permanent hardness of water by EDTA method. 15
3. Determination of chloride content of water sample by Argentometric method. 21
4. Determination of strength of given hydrochloric acid using pH meter. 25
5. Determination of strength of acids in a mixture of acids using conductivity meter. 29
6. Estimation of iron content of the given solution using potentiometer. 33
7. Conductometric titration of strong acid Vs strong base.

39


42

8


Estimation of copper content of the given solution by Iodometry 43
9 Estimation of sodium and potassium present in water using flame photometer 47






8



SHORT PROCEDURE:

CONTENTS
TITRATION
Estimation of alkalinity in water sample
(Std HCl Vs water sample)

Burette solution

Std. HCl


Pipette solution

Water sample


Indicator


(i) Phenolphthalein
(ii) Methyl orange


End point

(i) Disappearance of pink colour
(ii) Appearance of reddish orange colour






Relationship
between P &M
Nature of alkalinity
Amount of individual
alkalinities
OH
-
HCO 3
-


CO 3
2-

P = M

only OH
-

P or M

?
0.0

0.0


2P = M

only CO 3
2-


2P or M


0.0


0.0


?

P =0, M?0

only HCO 3
-



M



0.0



?

0.0


2P > M


OH
-
&CO 3
2-


OH
-
= 2P-M
CO 3
2-
= 2(M-P)


?

0.0

?

P < ? M




HCO 3
-
&CO 3
2-


HCO 3
-
= M-2P
CO 3
2-
= 2P

0.0 ? ?




9





Expt. No. 1 DETERMINATION OF ALKALINITY IN WATER
AIM
To determine the type and amounts of alkalinity in the given water sample. A standard solution of Na 2CO 3
of strength ____N is given.

PRINCIPLE
Alkalinity in water is due to the presence of soluble hydroxides, bicarbonates and carbonates.
Determination of various types and amounts of alkalinity is easily carried out by titration with standard HCl
employing the indicators phenolphthalein and methyl orange independently or in succession.

The following reactions occur when different types of alkalinity are neutralized with acid.

OH
?
+ H
+
? H 2O completed at pH 8.2-9.0 ----- (1)

CO 3
2 ?
+ H
+
? HCO 3
?
----- (2)

HCO 3
?
+ H
+
? (H 2CO 3) ? H 2O + CO 2, completed at pH 4.2-5.5 ----- (3)

Neutralisation (1) & (2) will be notified by phenolphthalein end-point while all the three will be

accounted by
methyl orange end-point. Bicarbonate in eqn. (3) may be due to the existence of soluble free bicarbonate salts and
bicarbonates resulting from half neutralization of soluble carbonates (eqn. (2))

Various steps to be followed

a) A known volume of water sample is titrated against std. HCl using first phenolphthalein indicator till
end-point (P) and the titration is continued without break using methyl orange indicator till the end-
point (M).



10


Titration

Estimation of Alkalinity in water sample

Standard HCl Vs Water sample Indicator: 1. Phenolphthalein
2. Methyl Orange


S.No.
Volume
of water
sample (ml)
Burette Reading
Concordant value

Initial Phenolphthalein End
Point (P)
Methyl Orange End
Point (M)

1

2






CALCULATION

Hydroxide ion alkalinity
Volume of HCl (2P-M) = ???????ml

Strength of HCl = ???????? N

Volume of water sample = ???????...ml

Strength of water sample = Volume of HCl (2P-M) x Strength of HCl
Volume of water sample

=

? Hydroxide ion alkalinity in terms of
CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ??????.mg/l







11




b) From the magnitudes of the P & M, the nature of alkalinity can be arrived as follows:

(i) P = M => Presence of only OH
-

(ii) 2P = M => Presence of only CO 3
2-

(iii) P =0, M=0 => Presence of only HCO 3
-
(iv) 2P > M => Presence of OH
-
& CO 3
2-
(v) 2P < M => Presence of HCO 3
-
& CO 3
2-

(Mixture of OH
-
& HCO3
-
is not listed since they do not exist together and are considered equivalent to CO 3
2-
).

PROCEDURE
TITRATION
ESTIMATION OF ALKALINITY IN WATER SAMPLE

Exactly 20 ml of water sample is pipetted out into a clean conical flask. Few drops of phenolphthalein
indicator are added and titrated against a standardized HCl taken in the burette. The end point is the
disappearance of pink colour, which is noted as P. Few drops of methyl orange indicator is added to the same
solution. The solution turns to yellow. The titration is continued further by adding same HCl without break till the
end point is reached. The end point is the colour change from yellow to reddish orange.

The experiment is repeated to get concordant values. From the magnitudes of P & M values, the type of
alkalinity present in the water sample is inferred and the individual amounts are calculated and reported.










12


Carbonate ion alkalinity

Volume of HCl 2 (M ? P) = ??? ????????ml

Strength of HCl = ??.?????..???...N

Volume of water sample =........................................ml

Strength of water sample = Volume of HCl 2 (M ? P) x Strength of HCl
Volume of water sample

= ???????????.. N




? Carbonate ion alkalinity
in terms of CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ???????????mg/l

















13





RESULT

1) The type of alkalinity present in the water sample = -------------------------ions.

2) The individual amounts of alkalinity present in the water sample:
Hydroxide ion alkalinity

= ----------------- ppm
Carbonate ion alkalinity = ------------------ ppm
Bicarbonate ion alkalinity = ----------------- ppm





VIVA-VOCE


1. What is meant by alkalinity?
2. What are the ions responsible for alkalinity?
3. Why OH
-
and HCO 3
?
ions cannot exist together in water?
4. What are the ions responsible for alkalinity when 2P > M?
5. What is the pH range for both in acidic and basic solutions?
6. What is the colour of phenolphthalein in an acid and in an alkaline solution?
7. What is the purpose of using two indicators in same titration?
8. What are the possible combinations of ions for alkalinity?
9. How is the amount of alkalinity expressed?
10. What are the types of indicator used in this experiment?







14

SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II TITRATION III
Standardisation of
EDTA
(EDTA Vs Std
Hard water)
Determination of
total hardness
(Std EDTA Vs Hard
water sample)
Determination of
permanent hardness
(Std EDTA Vs Boiled
Hard water sample)

Burette solution

EDTA solution

EDTA solution

EDTA solution

Pipette solution

20ml Std. hard water

20 ml hard water sample

20ml boiled hard water sample

Indicator

2 drops of EBT

2 drops of EBT

2 drops of EBT

Additional soln.


Ammoniacal Buffer
solution (5ml)

Ammoniacal Buffer solution
(5ml)

Ammoniacal Buffer solution
(5ml)
End point Wine - red to Steel blue Wine - red to steel blue Wine - red to Steel blue




STANDARDISATION OF EDTA
Titration - I
Std. HARD WATER Vs EDTA Indicator: EBT

S. No.
Volume of std hard
water (ml)
Burette Reading Volume of
EDTA
(V 1) (ml)
Concordant value

Initial

Final



Volume of std .hard water taken = 20 ml
Volume of EDTA consumed (V 1) = --------------- ml
1 ml of std.hard water = 1mg of CaCO 3
20 ml of std hard water = 20 mg of CaCO 3

V 1 ml of EDTA solution containing 20 mg of CaCO 3
1 ml of EDTA solution = 20 / V 1 mg of CaCO 3
= -----------------------mg of CaCO 3


15

Expt. No. 2 DETERMINATION OF TOTAL, TEMPORARY AND
PERMANENT HARDNESS OF WATER

AIM
To estimate the amount of total, temporary & permanent hardness in the given sample of water.

PRINCIPLE
The estimation is based on the complexometric titration.

(i) Total hardness of water is estimated by titrating against EDTA using EBT indicator.
EBT+M ?[EBT-M] (unstable complex)
(EBT-M) (Unstable complex) +EDTA ? [EDTA-M] (stable complex) +EBT
EBT indicator forms wine- red colored complex with metal ions present in water. On addition of EDTA
metal ions preferably forms complexes with EDTA and steel blue EBT indicator is set free. Therefore
change of colour from wine- red to steel blue denotes the end point.

(ii) Temporary hardness is removed by boiling the water.
Ca (HCO 3) 2 ? CaCO 3 +CO 2 ?+H 2O
Mg (HCO 3) 2 ? Mg(OH) 2 +2CO 2 ?
The precipitate is filtered and the remaining permanent hardness is estimated using EDTA.

PROCEDURE

TITRATION ? I
STANDARDISATION OF EDTA

Pipette out 20ml of standard hard water into a 250ml conical flask. Add 5ml of buffer solution and 3
drops of eriochrome black T indictor. Titrate the solution with EDTA from the burette until the colour
changes from wine- red to steel blue at the end point. Repeat the titration for concordant values. Let the
titre value be V 1ml.


16


Titration-II
SAMPLE HARD WATER Vs Std EDTA Indicator: EBT

S.No. Volume of sample
hard water (ml)
Burette Reading Volume of
EDTA
(V 2) (ml)
Concordant value

Initial

Final




CALCULATION

Calculation of total hardness


Volume of EDTA consumed (V 2) = ------------------------- ml
1ml of EDTA = 20 / V 1 mg of CaCO 3
V 2 ml of EDTA = 20 / V 1 x V 2 mg of CaCO 3

( i.e), If 20ml of sample hard water contains 20 x V 2 mg of CaCO 3 / V 1

Then 1000ml of water sample = 20 x V 2 x 1000 / V 1 x 20 mg of CaCO 3

= 1000 x V 2 / V 1 mg of CaCO3

Total hardness of given water sample = ---------------------ppm









17



DETERMINATION OF TOTAL HARDNESS

Pipette out 20ml of sample hard water into a clean conical flask. Add 5ml of buffer solution and 4 -5
drops of Eriochrome black -T indicator. Titrate the wine - red coloured solution with EDTA from the burette until
the colour steel blue appears at the end point. Repeat the titration for concordant values. Let the titre value be
V 2ml.



DETERMINATION OF PERMANENT HARDNESS

Take 100ml of hard water sample in a 500ml beaker and boil gently for about 1hour. Cool, filter it into a
100ml standard flask and make the volume up to the mark. Take 20ml of this solution and proceed it in the same
way as in titration (I). The volume of EDTA consumed corresponds to the permanent hardness of the water
sample. Let the titre value be V 3ml. Temporary hardness is calculated by subtracting permanent hardness from
total hardness.





















18




DETERMINATION OF PERMANENT HARDNESS
BOILED SAMPLE WATER Vs Std. EDTA Indicator: EBT


S.No.
Volume of boiled
hard water (ml)
Burette Reading (ml) Volume of
EDTA
(ml)

Concordant value

Initial Final



CALCULATION OF PERMANENT HARDNESS


Volume of EDTA consumed V 3 = ---------------------ml

1ml of EDTA = 20 / V 1 mg of CaCO 3

V 3ml of EDTA = 20 / V 1 x V 3 mg of CaCO 3

(i.e) 20 ml of boiled sample hard water = 20 / V 1 x V 3 mg of CaCO 3

Then 1000ml of boiled water sample = 20 / V 1 x V 3 / 20 * 1000mg of CaCO 3

= 1000 x V 3 / V 1 mg of CaCO 3

permanent hardness of boiled water sample = -----------------ppm

Temporary hardness of the given water sample = Total hardness ? Permanent hardness

= ------------------ppm

19







RESULT

(i) Total hardness of the given sample water = -------------- ppm.
(ii) Permanent hardness of the given sample water = --------------- ppm.
(iii) Temporary hardness of the given sample water = ----------------ppm.







VIVA-VOCE

1. Define ? Hard water
2. What is the structure of EDTA?
3. How will you calculate temporary hardness?
4. What is the role of the buffer in EDTA titration?
5. What is the permissible limit of hardness in drinking water?
6. Name the hardness producing ions present in water.
7. Name two salts which are responsible for temporary hardness.
8. Why is CaCO 3 taken as the standard?
9. Write the expansion of EDTA.
10. What is meant by EBT?











20





SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II
Standardisation of
AgNO 3
Estimation of Chloride
Burette solution

AgNO 3 solution

Std. AgNO 3 solution

Pipette solution

20ml std KCl solution

20 ml water sample

Indicator

1ml K 2CrO 4

1ml K 2CrO 4


End point

yellow to reddish brown

yellow to reddish brown

Titration I
Std. AgNO3 Vs KCl Indicator: Potassium Chromate













CALCULATION

Volume of KCl (V 1) = ------- ml

Strength of KCl (N 1) = ------- N

Volume of Silver Nitrate (V 2) = -------- ml

Strength of Siver Nitrate V 1N 1
N 2 =
V 1

= --------------------- N

S.No.
Volume of KCl
(ml)
Burette Reading (ml)
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

21




Expt.No. 3 ESTIMATION OF CHLORIDE CONTENT IN WATER
(ARGENTOMETRIC METHOD)
AIM
To estimate the amount of chloride present in given water sample by Argentometric method (Mohr?s
method). You are provided with standard solution of NaCl of strength --------N and a approximately N/10 solution of
Silver nitrate.

PRINCIPLE
The Chloride ion in the form of NaCl, KCl, CaCl 2, MgCl 2 etc., present in the water sample can be estimated
by Argentometric method or known as Mohr?s method. It is an example for precipitation titration. The reaction
between std. Sodium chloride and Silver nitrate is given below.
AgNO 3 + NaCl ? AgCl ? + NaNO 3
The completion of reaction can be observed by employing potassium chromate as the indicator. The end
point is the colour change from yellow to reddish brown due to the following reaction.
2AgNO 3 + K 2CrO 4 ? Ag 2CrO 4 ? + 2KNO 3
Potassium chromate indicator will not be precipitated as silver chromate until all the chlorides in the solution
have been precipitated as AgCl Since a precipitation reaction takes place in preference, this reaction takes place
only at the end point.

PROCEDURE
TITRATION I: STANDARDISATION OF SILVER NITRATE
Pipette out 20ml of standard sodium or potassium chloride solution into a clean conical flask. Add 1ml of 5%
K 2CrO 4 indicator, as the solution turns yellow in colour. Titrate it against silver nitrate solution taken in the burette.
Observe the nearness of the end point through the formation of coagulated silver chloride precipitate at the bottom
of the flask. Now add the silver nitrate drop by drop until the solution gets a faint reddish brown tinge. Repeat the
titration for concordant value. Let the volume of silver nitrate be V 2ml.





22






TITRATION - II

Std AgNO3 Vs WATER SAMPLE Indicator: Potassium Chromate













CALCULATION

Volume of Silver Nitrate (V 3) = ------------ ml

Strength of Siver Nitrate (N 3) = ------------- N

Volume of Water sample (V 4) = -------------- ml

Strength of Water sample V 3 N 3
(N 4) =
V 4

= ----------------- N

Amount of Chloride ion present in 1000 ml of the water sample = Equivalent mass of HCl X 1000


= N 4 x 35.46 x 1000


= -----------------mg/l







S.No.
Volume of water
sample (ml)
Burette Reading
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

23





TITRATION - II
ESTIMATION OF CHLORIDE ION

Pipette out 40 ml of the given water sample into a clean conical flask.To this sample add 1ml of 5% K 2CrO 4
indicator and titrate it against the standardized silver nitrate solution taken in the burette and continue the titration
until the solution produces a reddish brown colour. Note down the end point and repeat the titration for
concordance. Let the volume be V 3ml.







RESULT

The amount of chloride ion present in the water sample = ----------------- mg/l.




VIVA-VOCE

1. Why is this method known as Argentometric method?
2.
What is the chemical reaction between AgNO 3 and Cl
-
ions present in water?

3.
What is the form of Chloride ion present in water?

4. What is the reaction between AgNO 3 and K 2CrO 4 ?
5. What is the name of the method used in this titration?
6. Name the link solution used in the determination.
7. Name the solution used to standardize AgNO 3.
8. What is the indicator used in the determination?
9. How will you calculate the amount of chloride ion in the given solution?
10. What is the colour change in the titration?




24




SHORT PROCEDURE


CONTENTS

TITRATION I

TITRATION II
Burette solution

Std Sodium Hydroxide

Std Sodium Hydroxide

Pipette solution

20 ml hydrochloric acid 20 ml hydrochloric acid
Additional solution


20 ml distilled water

20 ml distilled water


End point



Sudden increase in pH
pH gradual increase

Equivalent Weight of HCl = 36.5







ROUGH GRAPH FAIR GRAPH











pH
? pH/ ? V





Volume of NaOH
(ml)
Volume of NaOH
(ml)





25



Expt. No. 4 DETERMINATION OF STRENGTH OF HCl by pH METRY

AIM
To determine the strength of given HCl by pH metry. A standard solution of 0.1N NaOH is provided.

PRINCIPLE
The pH of a solution is related to H
+
ion concentration by the following formula.

. pH = -log [ H
+
]

pH of a solution is indirectly related to H
+
ion concentration. When NaOH is added slowly to HCl, H
+
ions
get neutralized by OH
-
ions. The pH increases slowly.

H
+
+ Cl
-
+ Na
+
+ OH
-
? Na
+
+ Cl
-
+H 2O

When all H
+
ions of HCl are neutralized at the end point, addition of NaOH causes high increase in pH
because of the addition of excess OH
-
ions.

MATERIALS REQUIRED
pH meter, Glass electrode, Burette, Pipette, Std.NaOH, approximately N/10 HCl .

PROCEDURE

The burette is washed with distilled water, rinsed with the given std. Sodium hydroxide and filled with the
same solution. Exactly 10ml of the given HCl solution is pipetted out into a clean beaker. It is then diluted to 50ml
with distilled water. A glass electrode is dipped into the solution and its terminals are connected to a pH meter.

26

TITRATION - I
S.No Volume of
NaOH (ml)
pH
1

2

3

4

5

6

7

8

9

10


TITRATION - II



CALCULATION

Volume of NaOH (V 1) = ------------------- ml ( titre value)
Strength of NaOH (N 1) = ------------------- N
Volume of HCl (V 2) = ------------------ml
Strength of HCl (N 2) = ------------------ N
N 2 = V 1 N 1 / V 2
Strength of HCl = -------------------- N
Amount of HCl present in 1000ml of the given solution = Strength x equivalent weight of HCl
= ------------------ X 36.5
= --------------------- g
S.No Volume of
NaOH (ml)
pH
11

12

13

14

15

16

17

18

19

20

S.No
Volume of
NaOH (ml)
pH ?pH ?V ?pH / ?V
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
27



Now NaOH is gradually added from the burette to HCl taken in the beaker. pH of the solution is noted for
each addition of NaOH. This process is continued until 5 readings are taken after the end point.
A fair titration is performed to find the exact end point.





RESULT

(i) Strength of the given HCl solution = ---------------- N
(ii) Amount of HCl present in a litre of the solution = ---------------- g


VIVA-VOCE

1. What is meant by pH?
2. What is the name of the reference electrode used ?
3. Why does pH value increase suddenly at the end point?
4. What is the indicator used in the titration?
5. What is the pH range of human blood?
6. What is the unit of pH?
7. How will you calculate the amount of HCl?
8. How is glass electrode represented?
9. Why is glass electrode known as ion selective electrode?
10. What is the chemical reaction involved in this titration?





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?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





3


PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)
1. Fundamentals
To provide students with a solid foundation in Mathematics, Science and fundamentals of engineering,
enabling them to apply, to find solutions for engineering problems and use this knowledge to acquire higher
education
2. Core Competence
To train the students in chemistry practicals so that they apply their knowledge and training to compare,
and to analyze various engineering industrial problems to find solutions
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice this enables
them to find solutions for the real time problems in industry, and to design products
4. Professionalism
To inculcate professional and effective communication skills, leadership qualities and team spirit in the
students to make them multi-faceted personalities and develop their ability to relate engineering issues to
broader social context
5. Lifelong Learning/Ethics
To demonstrate and practice ethical and professional responsibilities in the industry and society in the
large, through commitment and lifelong learning needed for successful professional career






4


PROGRAMME OUTCOMES (POs)
To demonstrate and apply knowledge of Mathematics, Science and engineering fundamentals in the following
experiments.
1 .To estimate HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. To determine total, temporary & permanent hardness of water by EDTA method.
3. To determine DO content of water sample by Winkler?s method.
4. To determine chloride content of water sample by Argentometric method.
5. To estimate copper content of the given solution by Iodometry.
6. To determine strength of given hydrochloric acid using pH meter.
7. To determine strength of acids in a mixture of acids using conductivity meter.
8. To determine iron content of the given solution using potentiometer.
9. To estimate iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. To estimate sodium and potassium present in water using flame photometer.
11. To determine molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. To determine Pseudo first order kinetics ? ester hydrolysis.
13. To determine Corrosion experiment ? weight loss method.
14. To estimate CMC.
15. To estimate Phase change in a solid.
16. To determine strength of strong acid vs strong base using conductivity meter.











5

BS8161 - CHEMISTRY LABORATORY
SYLLABUS


? To make the student to acquire practical skills in the determination of water quality
parameters through volumetric and instrumental analysis.

? ???? ??? ???? ?? ???? ? ? ?To acquaint the students with the determination of molecular weight of a polymer by
viscometery.

LIST OF EXPERIMENTS:
1. Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. Determination of total, temporary & permanent hardness of water by EDTA method.
3. Determination of DO content of water sample by Winkler?s method.
4. Determination of chloride content of water sample by Argentometric method.
5. Estimation of copper content of the given solution by Iodometry.
6. Determination of strength of given hydrochloric acid using pH meter.
7. Determination of strength of acids in a mixture of acids using conductivity meter.
8. Estimation of iron content of the given solution using potentiometer.
9. Estimation of iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. Estimation of sodium and potassium present in water using flame photometer.
11. Determination of molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. Pseudo first order kinetics ? ester hydrolysis.
13. Corrosion experiment ? weight loss method.
14. Determination of CMC.
15. Phase change in a solid.
16. Conductometric titration of strong acid vs strong base.




? The students will be outfitted with hands-on knowledge in the quantitative chemical
analysis of water quality related parameters.
COURSE OBJECTIVES
COURSE OUTCOMES
6


INDEX [ SEMESTER ? I ]


S.No.



Date


Experiment

Date of
submission



Mark


Signature

1.

Estimation of HCl using Na 2CO 3 as
primary standard and Determination of
alkalinity in water sample.



2.


Determination of total, temporary &
permanent hardness of water by EDTA
method.



3.


Determination of chloride content of water
sample by argentometric method.



4.


Determination of strength of given
hydrochloric acid using pH meter.



5.


Determination of strength of acids in a
mixture of acids using conductivity meter.



6.


Estimation of iron content of the given
solution using potentiometer.



7.





Conductometric titration of strong acid Vs
strong base.



8.



Estimation of copper content of the given
solution by Iodometry


9.
Estimation of sodium and potassium
present in water using flame photometer




7




CONTENTS


S.No.


NAME OF EXPERIMENT

PAGE
No.
SEMESTER - I
1.
Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in
water sample.
09
2. Determination of total, temporary & permanent hardness of water by EDTA method. 15
3. Determination of chloride content of water sample by Argentometric method. 21
4. Determination of strength of given hydrochloric acid using pH meter. 25
5. Determination of strength of acids in a mixture of acids using conductivity meter. 29
6. Estimation of iron content of the given solution using potentiometer. 33
7. Conductometric titration of strong acid Vs strong base.

39


42

8


Estimation of copper content of the given solution by Iodometry 43
9 Estimation of sodium and potassium present in water using flame photometer 47






8



SHORT PROCEDURE:

CONTENTS
TITRATION
Estimation of alkalinity in water sample
(Std HCl Vs water sample)

Burette solution

Std. HCl


Pipette solution

Water sample


Indicator


(i) Phenolphthalein
(ii) Methyl orange


End point

(i) Disappearance of pink colour
(ii) Appearance of reddish orange colour






Relationship
between P &M
Nature of alkalinity
Amount of individual
alkalinities
OH
-
HCO 3
-


CO 3
2-

P = M

only OH
-

P or M

?
0.0

0.0


2P = M

only CO 3
2-


2P or M


0.0


0.0


?

P =0, M?0

only HCO 3
-



M



0.0



?

0.0


2P > M


OH
-
&CO 3
2-


OH
-
= 2P-M
CO 3
2-
= 2(M-P)


?

0.0

?

P < ? M




HCO 3
-
&CO 3
2-


HCO 3
-
= M-2P
CO 3
2-
= 2P

0.0 ? ?




9





Expt. No. 1 DETERMINATION OF ALKALINITY IN WATER
AIM
To determine the type and amounts of alkalinity in the given water sample. A standard solution of Na 2CO 3
of strength ____N is given.

PRINCIPLE
Alkalinity in water is due to the presence of soluble hydroxides, bicarbonates and carbonates.
Determination of various types and amounts of alkalinity is easily carried out by titration with standard HCl
employing the indicators phenolphthalein and methyl orange independently or in succession.

The following reactions occur when different types of alkalinity are neutralized with acid.

OH
?
+ H
+
? H 2O completed at pH 8.2-9.0 ----- (1)

CO 3
2 ?
+ H
+
? HCO 3
?
----- (2)

HCO 3
?
+ H
+
? (H 2CO 3) ? H 2O + CO 2, completed at pH 4.2-5.5 ----- (3)

Neutralisation (1) & (2) will be notified by phenolphthalein end-point while all the three will be

accounted by
methyl orange end-point. Bicarbonate in eqn. (3) may be due to the existence of soluble free bicarbonate salts and
bicarbonates resulting from half neutralization of soluble carbonates (eqn. (2))

Various steps to be followed

a) A known volume of water sample is titrated against std. HCl using first phenolphthalein indicator till
end-point (P) and the titration is continued without break using methyl orange indicator till the end-
point (M).



10


Titration

Estimation of Alkalinity in water sample

Standard HCl Vs Water sample Indicator: 1. Phenolphthalein
2. Methyl Orange


S.No.
Volume
of water
sample (ml)
Burette Reading
Concordant value

Initial Phenolphthalein End
Point (P)
Methyl Orange End
Point (M)

1

2






CALCULATION

Hydroxide ion alkalinity
Volume of HCl (2P-M) = ???????ml

Strength of HCl = ???????? N

Volume of water sample = ???????...ml

Strength of water sample = Volume of HCl (2P-M) x Strength of HCl
Volume of water sample

=

? Hydroxide ion alkalinity in terms of
CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ??????.mg/l







11




b) From the magnitudes of the P & M, the nature of alkalinity can be arrived as follows:

(i) P = M => Presence of only OH
-

(ii) 2P = M => Presence of only CO 3
2-

(iii) P =0, M=0 => Presence of only HCO 3
-
(iv) 2P > M => Presence of OH
-
& CO 3
2-
(v) 2P < M => Presence of HCO 3
-
& CO 3
2-

(Mixture of OH
-
& HCO3
-
is not listed since they do not exist together and are considered equivalent to CO 3
2-
).

PROCEDURE
TITRATION
ESTIMATION OF ALKALINITY IN WATER SAMPLE

Exactly 20 ml of water sample is pipetted out into a clean conical flask. Few drops of phenolphthalein
indicator are added and titrated against a standardized HCl taken in the burette. The end point is the
disappearance of pink colour, which is noted as P. Few drops of methyl orange indicator is added to the same
solution. The solution turns to yellow. The titration is continued further by adding same HCl without break till the
end point is reached. The end point is the colour change from yellow to reddish orange.

The experiment is repeated to get concordant values. From the magnitudes of P & M values, the type of
alkalinity present in the water sample is inferred and the individual amounts are calculated and reported.










12


Carbonate ion alkalinity

Volume of HCl 2 (M ? P) = ??? ????????ml

Strength of HCl = ??.?????..???...N

Volume of water sample =........................................ml

Strength of water sample = Volume of HCl 2 (M ? P) x Strength of HCl
Volume of water sample

= ???????????.. N




? Carbonate ion alkalinity
in terms of CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ???????????mg/l

















13





RESULT

1) The type of alkalinity present in the water sample = -------------------------ions.

2) The individual amounts of alkalinity present in the water sample:
Hydroxide ion alkalinity

= ----------------- ppm
Carbonate ion alkalinity = ------------------ ppm
Bicarbonate ion alkalinity = ----------------- ppm





VIVA-VOCE


1. What is meant by alkalinity?
2. What are the ions responsible for alkalinity?
3. Why OH
-
and HCO 3
?
ions cannot exist together in water?
4. What are the ions responsible for alkalinity when 2P > M?
5. What is the pH range for both in acidic and basic solutions?
6. What is the colour of phenolphthalein in an acid and in an alkaline solution?
7. What is the purpose of using two indicators in same titration?
8. What are the possible combinations of ions for alkalinity?
9. How is the amount of alkalinity expressed?
10. What are the types of indicator used in this experiment?







14

SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II TITRATION III
Standardisation of
EDTA
(EDTA Vs Std
Hard water)
Determination of
total hardness
(Std EDTA Vs Hard
water sample)
Determination of
permanent hardness
(Std EDTA Vs Boiled
Hard water sample)

Burette solution

EDTA solution

EDTA solution

EDTA solution

Pipette solution

20ml Std. hard water

20 ml hard water sample

20ml boiled hard water sample

Indicator

2 drops of EBT

2 drops of EBT

2 drops of EBT

Additional soln.


Ammoniacal Buffer
solution (5ml)

Ammoniacal Buffer solution
(5ml)

Ammoniacal Buffer solution
(5ml)
End point Wine - red to Steel blue Wine - red to steel blue Wine - red to Steel blue




STANDARDISATION OF EDTA
Titration - I
Std. HARD WATER Vs EDTA Indicator: EBT

S. No.
Volume of std hard
water (ml)
Burette Reading Volume of
EDTA
(V 1) (ml)
Concordant value

Initial

Final



Volume of std .hard water taken = 20 ml
Volume of EDTA consumed (V 1) = --------------- ml
1 ml of std.hard water = 1mg of CaCO 3
20 ml of std hard water = 20 mg of CaCO 3

V 1 ml of EDTA solution containing 20 mg of CaCO 3
1 ml of EDTA solution = 20 / V 1 mg of CaCO 3
= -----------------------mg of CaCO 3


15

Expt. No. 2 DETERMINATION OF TOTAL, TEMPORARY AND
PERMANENT HARDNESS OF WATER

AIM
To estimate the amount of total, temporary & permanent hardness in the given sample of water.

PRINCIPLE
The estimation is based on the complexometric titration.

(i) Total hardness of water is estimated by titrating against EDTA using EBT indicator.
EBT+M ?[EBT-M] (unstable complex)
(EBT-M) (Unstable complex) +EDTA ? [EDTA-M] (stable complex) +EBT
EBT indicator forms wine- red colored complex with metal ions present in water. On addition of EDTA
metal ions preferably forms complexes with EDTA and steel blue EBT indicator is set free. Therefore
change of colour from wine- red to steel blue denotes the end point.

(ii) Temporary hardness is removed by boiling the water.
Ca (HCO 3) 2 ? CaCO 3 +CO 2 ?+H 2O
Mg (HCO 3) 2 ? Mg(OH) 2 +2CO 2 ?
The precipitate is filtered and the remaining permanent hardness is estimated using EDTA.

PROCEDURE

TITRATION ? I
STANDARDISATION OF EDTA

Pipette out 20ml of standard hard water into a 250ml conical flask. Add 5ml of buffer solution and 3
drops of eriochrome black T indictor. Titrate the solution with EDTA from the burette until the colour
changes from wine- red to steel blue at the end point. Repeat the titration for concordant values. Let the
titre value be V 1ml.


16


Titration-II
SAMPLE HARD WATER Vs Std EDTA Indicator: EBT

S.No. Volume of sample
hard water (ml)
Burette Reading Volume of
EDTA
(V 2) (ml)
Concordant value

Initial

Final




CALCULATION

Calculation of total hardness


Volume of EDTA consumed (V 2) = ------------------------- ml
1ml of EDTA = 20 / V 1 mg of CaCO 3
V 2 ml of EDTA = 20 / V 1 x V 2 mg of CaCO 3

( i.e), If 20ml of sample hard water contains 20 x V 2 mg of CaCO 3 / V 1

Then 1000ml of water sample = 20 x V 2 x 1000 / V 1 x 20 mg of CaCO 3

= 1000 x V 2 / V 1 mg of CaCO3

Total hardness of given water sample = ---------------------ppm









17



DETERMINATION OF TOTAL HARDNESS

Pipette out 20ml of sample hard water into a clean conical flask. Add 5ml of buffer solution and 4 -5
drops of Eriochrome black -T indicator. Titrate the wine - red coloured solution with EDTA from the burette until
the colour steel blue appears at the end point. Repeat the titration for concordant values. Let the titre value be
V 2ml.



DETERMINATION OF PERMANENT HARDNESS

Take 100ml of hard water sample in a 500ml beaker and boil gently for about 1hour. Cool, filter it into a
100ml standard flask and make the volume up to the mark. Take 20ml of this solution and proceed it in the same
way as in titration (I). The volume of EDTA consumed corresponds to the permanent hardness of the water
sample. Let the titre value be V 3ml. Temporary hardness is calculated by subtracting permanent hardness from
total hardness.





















18




DETERMINATION OF PERMANENT HARDNESS
BOILED SAMPLE WATER Vs Std. EDTA Indicator: EBT


S.No.
Volume of boiled
hard water (ml)
Burette Reading (ml) Volume of
EDTA
(ml)

Concordant value

Initial Final



CALCULATION OF PERMANENT HARDNESS


Volume of EDTA consumed V 3 = ---------------------ml

1ml of EDTA = 20 / V 1 mg of CaCO 3

V 3ml of EDTA = 20 / V 1 x V 3 mg of CaCO 3

(i.e) 20 ml of boiled sample hard water = 20 / V 1 x V 3 mg of CaCO 3

Then 1000ml of boiled water sample = 20 / V 1 x V 3 / 20 * 1000mg of CaCO 3

= 1000 x V 3 / V 1 mg of CaCO 3

permanent hardness of boiled water sample = -----------------ppm

Temporary hardness of the given water sample = Total hardness ? Permanent hardness

= ------------------ppm

19







RESULT

(i) Total hardness of the given sample water = -------------- ppm.
(ii) Permanent hardness of the given sample water = --------------- ppm.
(iii) Temporary hardness of the given sample water = ----------------ppm.







VIVA-VOCE

1. Define ? Hard water
2. What is the structure of EDTA?
3. How will you calculate temporary hardness?
4. What is the role of the buffer in EDTA titration?
5. What is the permissible limit of hardness in drinking water?
6. Name the hardness producing ions present in water.
7. Name two salts which are responsible for temporary hardness.
8. Why is CaCO 3 taken as the standard?
9. Write the expansion of EDTA.
10. What is meant by EBT?











20





SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II
Standardisation of
AgNO 3
Estimation of Chloride
Burette solution

AgNO 3 solution

Std. AgNO 3 solution

Pipette solution

20ml std KCl solution

20 ml water sample

Indicator

1ml K 2CrO 4

1ml K 2CrO 4


End point

yellow to reddish brown

yellow to reddish brown

Titration I
Std. AgNO3 Vs KCl Indicator: Potassium Chromate













CALCULATION

Volume of KCl (V 1) = ------- ml

Strength of KCl (N 1) = ------- N

Volume of Silver Nitrate (V 2) = -------- ml

Strength of Siver Nitrate V 1N 1
N 2 =
V 1

= --------------------- N

S.No.
Volume of KCl
(ml)
Burette Reading (ml)
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

21




Expt.No. 3 ESTIMATION OF CHLORIDE CONTENT IN WATER
(ARGENTOMETRIC METHOD)
AIM
To estimate the amount of chloride present in given water sample by Argentometric method (Mohr?s
method). You are provided with standard solution of NaCl of strength --------N and a approximately N/10 solution of
Silver nitrate.

PRINCIPLE
The Chloride ion in the form of NaCl, KCl, CaCl 2, MgCl 2 etc., present in the water sample can be estimated
by Argentometric method or known as Mohr?s method. It is an example for precipitation titration. The reaction
between std. Sodium chloride and Silver nitrate is given below.
AgNO 3 + NaCl ? AgCl ? + NaNO 3
The completion of reaction can be observed by employing potassium chromate as the indicator. The end
point is the colour change from yellow to reddish brown due to the following reaction.
2AgNO 3 + K 2CrO 4 ? Ag 2CrO 4 ? + 2KNO 3
Potassium chromate indicator will not be precipitated as silver chromate until all the chlorides in the solution
have been precipitated as AgCl Since a precipitation reaction takes place in preference, this reaction takes place
only at the end point.

PROCEDURE
TITRATION I: STANDARDISATION OF SILVER NITRATE
Pipette out 20ml of standard sodium or potassium chloride solution into a clean conical flask. Add 1ml of 5%
K 2CrO 4 indicator, as the solution turns yellow in colour. Titrate it against silver nitrate solution taken in the burette.
Observe the nearness of the end point through the formation of coagulated silver chloride precipitate at the bottom
of the flask. Now add the silver nitrate drop by drop until the solution gets a faint reddish brown tinge. Repeat the
titration for concordant value. Let the volume of silver nitrate be V 2ml.





22






TITRATION - II

Std AgNO3 Vs WATER SAMPLE Indicator: Potassium Chromate













CALCULATION

Volume of Silver Nitrate (V 3) = ------------ ml

Strength of Siver Nitrate (N 3) = ------------- N

Volume of Water sample (V 4) = -------------- ml

Strength of Water sample V 3 N 3
(N 4) =
V 4

= ----------------- N

Amount of Chloride ion present in 1000 ml of the water sample = Equivalent mass of HCl X 1000


= N 4 x 35.46 x 1000


= -----------------mg/l







S.No.
Volume of water
sample (ml)
Burette Reading
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

23





TITRATION - II
ESTIMATION OF CHLORIDE ION

Pipette out 40 ml of the given water sample into a clean conical flask.To this sample add 1ml of 5% K 2CrO 4
indicator and titrate it against the standardized silver nitrate solution taken in the burette and continue the titration
until the solution produces a reddish brown colour. Note down the end point and repeat the titration for
concordance. Let the volume be V 3ml.







RESULT

The amount of chloride ion present in the water sample = ----------------- mg/l.




VIVA-VOCE

1. Why is this method known as Argentometric method?
2.
What is the chemical reaction between AgNO 3 and Cl
-
ions present in water?

3.
What is the form of Chloride ion present in water?

4. What is the reaction between AgNO 3 and K 2CrO 4 ?
5. What is the name of the method used in this titration?
6. Name the link solution used in the determination.
7. Name the solution used to standardize AgNO 3.
8. What is the indicator used in the determination?
9. How will you calculate the amount of chloride ion in the given solution?
10. What is the colour change in the titration?




24




SHORT PROCEDURE


CONTENTS

TITRATION I

TITRATION II
Burette solution

Std Sodium Hydroxide

Std Sodium Hydroxide

Pipette solution

20 ml hydrochloric acid 20 ml hydrochloric acid
Additional solution


20 ml distilled water

20 ml distilled water


End point



Sudden increase in pH
pH gradual increase

Equivalent Weight of HCl = 36.5







ROUGH GRAPH FAIR GRAPH











pH
? pH/ ? V





Volume of NaOH
(ml)
Volume of NaOH
(ml)





25



Expt. No. 4 DETERMINATION OF STRENGTH OF HCl by pH METRY

AIM
To determine the strength of given HCl by pH metry. A standard solution of 0.1N NaOH is provided.

PRINCIPLE
The pH of a solution is related to H
+
ion concentration by the following formula.

. pH = -log [ H
+
]

pH of a solution is indirectly related to H
+
ion concentration. When NaOH is added slowly to HCl, H
+
ions
get neutralized by OH
-
ions. The pH increases slowly.

H
+
+ Cl
-
+ Na
+
+ OH
-
? Na
+
+ Cl
-
+H 2O

When all H
+
ions of HCl are neutralized at the end point, addition of NaOH causes high increase in pH
because of the addition of excess OH
-
ions.

MATERIALS REQUIRED
pH meter, Glass electrode, Burette, Pipette, Std.NaOH, approximately N/10 HCl .

PROCEDURE

The burette is washed with distilled water, rinsed with the given std. Sodium hydroxide and filled with the
same solution. Exactly 10ml of the given HCl solution is pipetted out into a clean beaker. It is then diluted to 50ml
with distilled water. A glass electrode is dipped into the solution and its terminals are connected to a pH meter.

26

TITRATION - I
S.No Volume of
NaOH (ml)
pH
1

2

3

4

5

6

7

8

9

10


TITRATION - II



CALCULATION

Volume of NaOH (V 1) = ------------------- ml ( titre value)
Strength of NaOH (N 1) = ------------------- N
Volume of HCl (V 2) = ------------------ml
Strength of HCl (N 2) = ------------------ N
N 2 = V 1 N 1 / V 2
Strength of HCl = -------------------- N
Amount of HCl present in 1000ml of the given solution = Strength x equivalent weight of HCl
= ------------------ X 36.5
= --------------------- g
S.No Volume of
NaOH (ml)
pH
11

12

13

14

15

16

17

18

19

20

S.No
Volume of
NaOH (ml)
pH ?pH ?V ?pH / ?V
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
27



Now NaOH is gradually added from the burette to HCl taken in the beaker. pH of the solution is noted for
each addition of NaOH. This process is continued until 5 readings are taken after the end point.
A fair titration is performed to find the exact end point.





RESULT

(i) Strength of the given HCl solution = ---------------- N
(ii) Amount of HCl present in a litre of the solution = ---------------- g


VIVA-VOCE

1. What is meant by pH?
2. What is the name of the reference electrode used ?
3. Why does pH value increase suddenly at the end point?
4. What is the indicator used in the titration?
5. What is the pH range of human blood?
6. What is the unit of pH?
7. How will you calculate the amount of HCl?
8. How is glass electrode represented?
9. Why is glass electrode known as ion selective electrode?
10. What is the chemical reaction involved in this titration?





28




SHORT PROCEDURE


CONTENTS
TITRATION
Burette solution

Std Sodium Hydroxide

Pipette solution

20 ml mixture of acid (HCl+ CH 3COOH)


Additional solution

20 ml distilled water


End point

Conductivity decreases-slowly increases-Sudden increase



Equivalent Weight of HCl = 36.5


Equivalent Weight of CH 3COOH = 60



MODEL GRAPH


Conductance
Volume of NaOH
Mixture of Acids






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?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





3


PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)
1. Fundamentals
To provide students with a solid foundation in Mathematics, Science and fundamentals of engineering,
enabling them to apply, to find solutions for engineering problems and use this knowledge to acquire higher
education
2. Core Competence
To train the students in chemistry practicals so that they apply their knowledge and training to compare,
and to analyze various engineering industrial problems to find solutions
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice this enables
them to find solutions for the real time problems in industry, and to design products
4. Professionalism
To inculcate professional and effective communication skills, leadership qualities and team spirit in the
students to make them multi-faceted personalities and develop their ability to relate engineering issues to
broader social context
5. Lifelong Learning/Ethics
To demonstrate and practice ethical and professional responsibilities in the industry and society in the
large, through commitment and lifelong learning needed for successful professional career






4


PROGRAMME OUTCOMES (POs)
To demonstrate and apply knowledge of Mathematics, Science and engineering fundamentals in the following
experiments.
1 .To estimate HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. To determine total, temporary & permanent hardness of water by EDTA method.
3. To determine DO content of water sample by Winkler?s method.
4. To determine chloride content of water sample by Argentometric method.
5. To estimate copper content of the given solution by Iodometry.
6. To determine strength of given hydrochloric acid using pH meter.
7. To determine strength of acids in a mixture of acids using conductivity meter.
8. To determine iron content of the given solution using potentiometer.
9. To estimate iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. To estimate sodium and potassium present in water using flame photometer.
11. To determine molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. To determine Pseudo first order kinetics ? ester hydrolysis.
13. To determine Corrosion experiment ? weight loss method.
14. To estimate CMC.
15. To estimate Phase change in a solid.
16. To determine strength of strong acid vs strong base using conductivity meter.











5

BS8161 - CHEMISTRY LABORATORY
SYLLABUS


? To make the student to acquire practical skills in the determination of water quality
parameters through volumetric and instrumental analysis.

? ???? ??? ???? ?? ???? ? ? ?To acquaint the students with the determination of molecular weight of a polymer by
viscometery.

LIST OF EXPERIMENTS:
1. Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. Determination of total, temporary & permanent hardness of water by EDTA method.
3. Determination of DO content of water sample by Winkler?s method.
4. Determination of chloride content of water sample by Argentometric method.
5. Estimation of copper content of the given solution by Iodometry.
6. Determination of strength of given hydrochloric acid using pH meter.
7. Determination of strength of acids in a mixture of acids using conductivity meter.
8. Estimation of iron content of the given solution using potentiometer.
9. Estimation of iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. Estimation of sodium and potassium present in water using flame photometer.
11. Determination of molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. Pseudo first order kinetics ? ester hydrolysis.
13. Corrosion experiment ? weight loss method.
14. Determination of CMC.
15. Phase change in a solid.
16. Conductometric titration of strong acid vs strong base.




? The students will be outfitted with hands-on knowledge in the quantitative chemical
analysis of water quality related parameters.
COURSE OBJECTIVES
COURSE OUTCOMES
6


INDEX [ SEMESTER ? I ]


S.No.



Date


Experiment

Date of
submission



Mark


Signature

1.

Estimation of HCl using Na 2CO 3 as
primary standard and Determination of
alkalinity in water sample.



2.


Determination of total, temporary &
permanent hardness of water by EDTA
method.



3.


Determination of chloride content of water
sample by argentometric method.



4.


Determination of strength of given
hydrochloric acid using pH meter.



5.


Determination of strength of acids in a
mixture of acids using conductivity meter.



6.


Estimation of iron content of the given
solution using potentiometer.



7.





Conductometric titration of strong acid Vs
strong base.



8.



Estimation of copper content of the given
solution by Iodometry


9.
Estimation of sodium and potassium
present in water using flame photometer




7




CONTENTS


S.No.


NAME OF EXPERIMENT

PAGE
No.
SEMESTER - I
1.
Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in
water sample.
09
2. Determination of total, temporary & permanent hardness of water by EDTA method. 15
3. Determination of chloride content of water sample by Argentometric method. 21
4. Determination of strength of given hydrochloric acid using pH meter. 25
5. Determination of strength of acids in a mixture of acids using conductivity meter. 29
6. Estimation of iron content of the given solution using potentiometer. 33
7. Conductometric titration of strong acid Vs strong base.

39


42

8


Estimation of copper content of the given solution by Iodometry 43
9 Estimation of sodium and potassium present in water using flame photometer 47






8



SHORT PROCEDURE:

CONTENTS
TITRATION
Estimation of alkalinity in water sample
(Std HCl Vs water sample)

Burette solution

Std. HCl


Pipette solution

Water sample


Indicator


(i) Phenolphthalein
(ii) Methyl orange


End point

(i) Disappearance of pink colour
(ii) Appearance of reddish orange colour






Relationship
between P &M
Nature of alkalinity
Amount of individual
alkalinities
OH
-
HCO 3
-


CO 3
2-

P = M

only OH
-

P or M

?
0.0

0.0


2P = M

only CO 3
2-


2P or M


0.0


0.0


?

P =0, M?0

only HCO 3
-



M



0.0



?

0.0


2P > M


OH
-
&CO 3
2-


OH
-
= 2P-M
CO 3
2-
= 2(M-P)


?

0.0

?

P < ? M




HCO 3
-
&CO 3
2-


HCO 3
-
= M-2P
CO 3
2-
= 2P

0.0 ? ?




9





Expt. No. 1 DETERMINATION OF ALKALINITY IN WATER
AIM
To determine the type and amounts of alkalinity in the given water sample. A standard solution of Na 2CO 3
of strength ____N is given.

PRINCIPLE
Alkalinity in water is due to the presence of soluble hydroxides, bicarbonates and carbonates.
Determination of various types and amounts of alkalinity is easily carried out by titration with standard HCl
employing the indicators phenolphthalein and methyl orange independently or in succession.

The following reactions occur when different types of alkalinity are neutralized with acid.

OH
?
+ H
+
? H 2O completed at pH 8.2-9.0 ----- (1)

CO 3
2 ?
+ H
+
? HCO 3
?
----- (2)

HCO 3
?
+ H
+
? (H 2CO 3) ? H 2O + CO 2, completed at pH 4.2-5.5 ----- (3)

Neutralisation (1) & (2) will be notified by phenolphthalein end-point while all the three will be

accounted by
methyl orange end-point. Bicarbonate in eqn. (3) may be due to the existence of soluble free bicarbonate salts and
bicarbonates resulting from half neutralization of soluble carbonates (eqn. (2))

Various steps to be followed

a) A known volume of water sample is titrated against std. HCl using first phenolphthalein indicator till
end-point (P) and the titration is continued without break using methyl orange indicator till the end-
point (M).



10


Titration

Estimation of Alkalinity in water sample

Standard HCl Vs Water sample Indicator: 1. Phenolphthalein
2. Methyl Orange


S.No.
Volume
of water
sample (ml)
Burette Reading
Concordant value

Initial Phenolphthalein End
Point (P)
Methyl Orange End
Point (M)

1

2






CALCULATION

Hydroxide ion alkalinity
Volume of HCl (2P-M) = ???????ml

Strength of HCl = ???????? N

Volume of water sample = ???????...ml

Strength of water sample = Volume of HCl (2P-M) x Strength of HCl
Volume of water sample

=

? Hydroxide ion alkalinity in terms of
CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ??????.mg/l







11




b) From the magnitudes of the P & M, the nature of alkalinity can be arrived as follows:

(i) P = M => Presence of only OH
-

(ii) 2P = M => Presence of only CO 3
2-

(iii) P =0, M=0 => Presence of only HCO 3
-
(iv) 2P > M => Presence of OH
-
& CO 3
2-
(v) 2P < M => Presence of HCO 3
-
& CO 3
2-

(Mixture of OH
-
& HCO3
-
is not listed since they do not exist together and are considered equivalent to CO 3
2-
).

PROCEDURE
TITRATION
ESTIMATION OF ALKALINITY IN WATER SAMPLE

Exactly 20 ml of water sample is pipetted out into a clean conical flask. Few drops of phenolphthalein
indicator are added and titrated against a standardized HCl taken in the burette. The end point is the
disappearance of pink colour, which is noted as P. Few drops of methyl orange indicator is added to the same
solution. The solution turns to yellow. The titration is continued further by adding same HCl without break till the
end point is reached. The end point is the colour change from yellow to reddish orange.

The experiment is repeated to get concordant values. From the magnitudes of P & M values, the type of
alkalinity present in the water sample is inferred and the individual amounts are calculated and reported.










12


Carbonate ion alkalinity

Volume of HCl 2 (M ? P) = ??? ????????ml

Strength of HCl = ??.?????..???...N

Volume of water sample =........................................ml

Strength of water sample = Volume of HCl 2 (M ? P) x Strength of HCl
Volume of water sample

= ???????????.. N




? Carbonate ion alkalinity
in terms of CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ???????????mg/l

















13





RESULT

1) The type of alkalinity present in the water sample = -------------------------ions.

2) The individual amounts of alkalinity present in the water sample:
Hydroxide ion alkalinity

= ----------------- ppm
Carbonate ion alkalinity = ------------------ ppm
Bicarbonate ion alkalinity = ----------------- ppm





VIVA-VOCE


1. What is meant by alkalinity?
2. What are the ions responsible for alkalinity?
3. Why OH
-
and HCO 3
?
ions cannot exist together in water?
4. What are the ions responsible for alkalinity when 2P > M?
5. What is the pH range for both in acidic and basic solutions?
6. What is the colour of phenolphthalein in an acid and in an alkaline solution?
7. What is the purpose of using two indicators in same titration?
8. What are the possible combinations of ions for alkalinity?
9. How is the amount of alkalinity expressed?
10. What are the types of indicator used in this experiment?







14

SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II TITRATION III
Standardisation of
EDTA
(EDTA Vs Std
Hard water)
Determination of
total hardness
(Std EDTA Vs Hard
water sample)
Determination of
permanent hardness
(Std EDTA Vs Boiled
Hard water sample)

Burette solution

EDTA solution

EDTA solution

EDTA solution

Pipette solution

20ml Std. hard water

20 ml hard water sample

20ml boiled hard water sample

Indicator

2 drops of EBT

2 drops of EBT

2 drops of EBT

Additional soln.


Ammoniacal Buffer
solution (5ml)

Ammoniacal Buffer solution
(5ml)

Ammoniacal Buffer solution
(5ml)
End point Wine - red to Steel blue Wine - red to steel blue Wine - red to Steel blue




STANDARDISATION OF EDTA
Titration - I
Std. HARD WATER Vs EDTA Indicator: EBT

S. No.
Volume of std hard
water (ml)
Burette Reading Volume of
EDTA
(V 1) (ml)
Concordant value

Initial

Final



Volume of std .hard water taken = 20 ml
Volume of EDTA consumed (V 1) = --------------- ml
1 ml of std.hard water = 1mg of CaCO 3
20 ml of std hard water = 20 mg of CaCO 3

V 1 ml of EDTA solution containing 20 mg of CaCO 3
1 ml of EDTA solution = 20 / V 1 mg of CaCO 3
= -----------------------mg of CaCO 3


15

Expt. No. 2 DETERMINATION OF TOTAL, TEMPORARY AND
PERMANENT HARDNESS OF WATER

AIM
To estimate the amount of total, temporary & permanent hardness in the given sample of water.

PRINCIPLE
The estimation is based on the complexometric titration.

(i) Total hardness of water is estimated by titrating against EDTA using EBT indicator.
EBT+M ?[EBT-M] (unstable complex)
(EBT-M) (Unstable complex) +EDTA ? [EDTA-M] (stable complex) +EBT
EBT indicator forms wine- red colored complex with metal ions present in water. On addition of EDTA
metal ions preferably forms complexes with EDTA and steel blue EBT indicator is set free. Therefore
change of colour from wine- red to steel blue denotes the end point.

(ii) Temporary hardness is removed by boiling the water.
Ca (HCO 3) 2 ? CaCO 3 +CO 2 ?+H 2O
Mg (HCO 3) 2 ? Mg(OH) 2 +2CO 2 ?
The precipitate is filtered and the remaining permanent hardness is estimated using EDTA.

PROCEDURE

TITRATION ? I
STANDARDISATION OF EDTA

Pipette out 20ml of standard hard water into a 250ml conical flask. Add 5ml of buffer solution and 3
drops of eriochrome black T indictor. Titrate the solution with EDTA from the burette until the colour
changes from wine- red to steel blue at the end point. Repeat the titration for concordant values. Let the
titre value be V 1ml.


16


Titration-II
SAMPLE HARD WATER Vs Std EDTA Indicator: EBT

S.No. Volume of sample
hard water (ml)
Burette Reading Volume of
EDTA
(V 2) (ml)
Concordant value

Initial

Final




CALCULATION

Calculation of total hardness


Volume of EDTA consumed (V 2) = ------------------------- ml
1ml of EDTA = 20 / V 1 mg of CaCO 3
V 2 ml of EDTA = 20 / V 1 x V 2 mg of CaCO 3

( i.e), If 20ml of sample hard water contains 20 x V 2 mg of CaCO 3 / V 1

Then 1000ml of water sample = 20 x V 2 x 1000 / V 1 x 20 mg of CaCO 3

= 1000 x V 2 / V 1 mg of CaCO3

Total hardness of given water sample = ---------------------ppm









17



DETERMINATION OF TOTAL HARDNESS

Pipette out 20ml of sample hard water into a clean conical flask. Add 5ml of buffer solution and 4 -5
drops of Eriochrome black -T indicator. Titrate the wine - red coloured solution with EDTA from the burette until
the colour steel blue appears at the end point. Repeat the titration for concordant values. Let the titre value be
V 2ml.



DETERMINATION OF PERMANENT HARDNESS

Take 100ml of hard water sample in a 500ml beaker and boil gently for about 1hour. Cool, filter it into a
100ml standard flask and make the volume up to the mark. Take 20ml of this solution and proceed it in the same
way as in titration (I). The volume of EDTA consumed corresponds to the permanent hardness of the water
sample. Let the titre value be V 3ml. Temporary hardness is calculated by subtracting permanent hardness from
total hardness.





















18




DETERMINATION OF PERMANENT HARDNESS
BOILED SAMPLE WATER Vs Std. EDTA Indicator: EBT


S.No.
Volume of boiled
hard water (ml)
Burette Reading (ml) Volume of
EDTA
(ml)

Concordant value

Initial Final



CALCULATION OF PERMANENT HARDNESS


Volume of EDTA consumed V 3 = ---------------------ml

1ml of EDTA = 20 / V 1 mg of CaCO 3

V 3ml of EDTA = 20 / V 1 x V 3 mg of CaCO 3

(i.e) 20 ml of boiled sample hard water = 20 / V 1 x V 3 mg of CaCO 3

Then 1000ml of boiled water sample = 20 / V 1 x V 3 / 20 * 1000mg of CaCO 3

= 1000 x V 3 / V 1 mg of CaCO 3

permanent hardness of boiled water sample = -----------------ppm

Temporary hardness of the given water sample = Total hardness ? Permanent hardness

= ------------------ppm

19







RESULT

(i) Total hardness of the given sample water = -------------- ppm.
(ii) Permanent hardness of the given sample water = --------------- ppm.
(iii) Temporary hardness of the given sample water = ----------------ppm.







VIVA-VOCE

1. Define ? Hard water
2. What is the structure of EDTA?
3. How will you calculate temporary hardness?
4. What is the role of the buffer in EDTA titration?
5. What is the permissible limit of hardness in drinking water?
6. Name the hardness producing ions present in water.
7. Name two salts which are responsible for temporary hardness.
8. Why is CaCO 3 taken as the standard?
9. Write the expansion of EDTA.
10. What is meant by EBT?











20





SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II
Standardisation of
AgNO 3
Estimation of Chloride
Burette solution

AgNO 3 solution

Std. AgNO 3 solution

Pipette solution

20ml std KCl solution

20 ml water sample

Indicator

1ml K 2CrO 4

1ml K 2CrO 4


End point

yellow to reddish brown

yellow to reddish brown

Titration I
Std. AgNO3 Vs KCl Indicator: Potassium Chromate













CALCULATION

Volume of KCl (V 1) = ------- ml

Strength of KCl (N 1) = ------- N

Volume of Silver Nitrate (V 2) = -------- ml

Strength of Siver Nitrate V 1N 1
N 2 =
V 1

= --------------------- N

S.No.
Volume of KCl
(ml)
Burette Reading (ml)
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

21




Expt.No. 3 ESTIMATION OF CHLORIDE CONTENT IN WATER
(ARGENTOMETRIC METHOD)
AIM
To estimate the amount of chloride present in given water sample by Argentometric method (Mohr?s
method). You are provided with standard solution of NaCl of strength --------N and a approximately N/10 solution of
Silver nitrate.

PRINCIPLE
The Chloride ion in the form of NaCl, KCl, CaCl 2, MgCl 2 etc., present in the water sample can be estimated
by Argentometric method or known as Mohr?s method. It is an example for precipitation titration. The reaction
between std. Sodium chloride and Silver nitrate is given below.
AgNO 3 + NaCl ? AgCl ? + NaNO 3
The completion of reaction can be observed by employing potassium chromate as the indicator. The end
point is the colour change from yellow to reddish brown due to the following reaction.
2AgNO 3 + K 2CrO 4 ? Ag 2CrO 4 ? + 2KNO 3
Potassium chromate indicator will not be precipitated as silver chromate until all the chlorides in the solution
have been precipitated as AgCl Since a precipitation reaction takes place in preference, this reaction takes place
only at the end point.

PROCEDURE
TITRATION I: STANDARDISATION OF SILVER NITRATE
Pipette out 20ml of standard sodium or potassium chloride solution into a clean conical flask. Add 1ml of 5%
K 2CrO 4 indicator, as the solution turns yellow in colour. Titrate it against silver nitrate solution taken in the burette.
Observe the nearness of the end point through the formation of coagulated silver chloride precipitate at the bottom
of the flask. Now add the silver nitrate drop by drop until the solution gets a faint reddish brown tinge. Repeat the
titration for concordant value. Let the volume of silver nitrate be V 2ml.





22






TITRATION - II

Std AgNO3 Vs WATER SAMPLE Indicator: Potassium Chromate













CALCULATION

Volume of Silver Nitrate (V 3) = ------------ ml

Strength of Siver Nitrate (N 3) = ------------- N

Volume of Water sample (V 4) = -------------- ml

Strength of Water sample V 3 N 3
(N 4) =
V 4

= ----------------- N

Amount of Chloride ion present in 1000 ml of the water sample = Equivalent mass of HCl X 1000


= N 4 x 35.46 x 1000


= -----------------mg/l







S.No.
Volume of water
sample (ml)
Burette Reading
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

23





TITRATION - II
ESTIMATION OF CHLORIDE ION

Pipette out 40 ml of the given water sample into a clean conical flask.To this sample add 1ml of 5% K 2CrO 4
indicator and titrate it against the standardized silver nitrate solution taken in the burette and continue the titration
until the solution produces a reddish brown colour. Note down the end point and repeat the titration for
concordance. Let the volume be V 3ml.







RESULT

The amount of chloride ion present in the water sample = ----------------- mg/l.




VIVA-VOCE

1. Why is this method known as Argentometric method?
2.
What is the chemical reaction between AgNO 3 and Cl
-
ions present in water?

3.
What is the form of Chloride ion present in water?

4. What is the reaction between AgNO 3 and K 2CrO 4 ?
5. What is the name of the method used in this titration?
6. Name the link solution used in the determination.
7. Name the solution used to standardize AgNO 3.
8. What is the indicator used in the determination?
9. How will you calculate the amount of chloride ion in the given solution?
10. What is the colour change in the titration?




24




SHORT PROCEDURE


CONTENTS

TITRATION I

TITRATION II
Burette solution

Std Sodium Hydroxide

Std Sodium Hydroxide

Pipette solution

20 ml hydrochloric acid 20 ml hydrochloric acid
Additional solution


20 ml distilled water

20 ml distilled water


End point



Sudden increase in pH
pH gradual increase

Equivalent Weight of HCl = 36.5







ROUGH GRAPH FAIR GRAPH











pH
? pH/ ? V





Volume of NaOH
(ml)
Volume of NaOH
(ml)





25



Expt. No. 4 DETERMINATION OF STRENGTH OF HCl by pH METRY

AIM
To determine the strength of given HCl by pH metry. A standard solution of 0.1N NaOH is provided.

PRINCIPLE
The pH of a solution is related to H
+
ion concentration by the following formula.

. pH = -log [ H
+
]

pH of a solution is indirectly related to H
+
ion concentration. When NaOH is added slowly to HCl, H
+
ions
get neutralized by OH
-
ions. The pH increases slowly.

H
+
+ Cl
-
+ Na
+
+ OH
-
? Na
+
+ Cl
-
+H 2O

When all H
+
ions of HCl are neutralized at the end point, addition of NaOH causes high increase in pH
because of the addition of excess OH
-
ions.

MATERIALS REQUIRED
pH meter, Glass electrode, Burette, Pipette, Std.NaOH, approximately N/10 HCl .

PROCEDURE

The burette is washed with distilled water, rinsed with the given std. Sodium hydroxide and filled with the
same solution. Exactly 10ml of the given HCl solution is pipetted out into a clean beaker. It is then diluted to 50ml
with distilled water. A glass electrode is dipped into the solution and its terminals are connected to a pH meter.

26

TITRATION - I
S.No Volume of
NaOH (ml)
pH
1

2

3

4

5

6

7

8

9

10


TITRATION - II



CALCULATION

Volume of NaOH (V 1) = ------------------- ml ( titre value)
Strength of NaOH (N 1) = ------------------- N
Volume of HCl (V 2) = ------------------ml
Strength of HCl (N 2) = ------------------ N
N 2 = V 1 N 1 / V 2
Strength of HCl = -------------------- N
Amount of HCl present in 1000ml of the given solution = Strength x equivalent weight of HCl
= ------------------ X 36.5
= --------------------- g
S.No Volume of
NaOH (ml)
pH
11

12

13

14

15

16

17

18

19

20

S.No
Volume of
NaOH (ml)
pH ?pH ?V ?pH / ?V
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
27



Now NaOH is gradually added from the burette to HCl taken in the beaker. pH of the solution is noted for
each addition of NaOH. This process is continued until 5 readings are taken after the end point.
A fair titration is performed to find the exact end point.





RESULT

(i) Strength of the given HCl solution = ---------------- N
(ii) Amount of HCl present in a litre of the solution = ---------------- g


VIVA-VOCE

1. What is meant by pH?
2. What is the name of the reference electrode used ?
3. Why does pH value increase suddenly at the end point?
4. What is the indicator used in the titration?
5. What is the pH range of human blood?
6. What is the unit of pH?
7. How will you calculate the amount of HCl?
8. How is glass electrode represented?
9. Why is glass electrode known as ion selective electrode?
10. What is the chemical reaction involved in this titration?





28




SHORT PROCEDURE


CONTENTS
TITRATION
Burette solution

Std Sodium Hydroxide

Pipette solution

20 ml mixture of acid (HCl+ CH 3COOH)


Additional solution

20 ml distilled water


End point

Conductivity decreases-slowly increases-Sudden increase



Equivalent Weight of HCl = 36.5


Equivalent Weight of CH 3COOH = 60



MODEL GRAPH


Conductance
Volume of NaOH
Mixture of Acids






29




Expt. No. 5 CONDUCTOMETRIC TITRATION OF MIXTURE
OF ACIDS

AIM
To determine the amount of a strong acid and a weak acid present in the given solution.

PRINCIPLE

Solution of electrolytes conducts electricity due to the presence of ions. Since specific conductance of a
solution is proportional to the concentration of ions in it, conductance of the solution is measured during the titration.

HCl + NaOH ? NaCl + H 2O (I neutralization)

CH 3COOH + NaOH ? CH 3COONa + H 2O (II neutralization)

When a solution of HCl is treated with NaOH the fast moving hydrogen ions are progressively replaced by
slow moving sodium ions. As a result conductance of the solution decreases. This decrease will take place until the
first neutralisation point is reached. Further addition of alkali results in formation of sodium acetate.

Since sodium acetate is stronger than acetic acid conductivity slowly increases until all acetic acid is
completely neutralized.(II Neutralisation) This is due to the presence of fast moving OH
-
ions. Anymore addition of
alkali increases the conductance sharply.

PROCEDURE
The burette is filled with NaOH solution upto zero mark. The given unknown solution (mixture of a weak &
a strong acid) is transferred into a 100ml standard flask and made upto the mark with distilled water. 20ml of the
made up solution is pipetted out into a clean 100ml beaker. The solution is diluted to 20ml using distilled water. A
conductivity cell is dipped into the solution and the terminals are connected to a conductivity meter.
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?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





3


PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)
1. Fundamentals
To provide students with a solid foundation in Mathematics, Science and fundamentals of engineering,
enabling them to apply, to find solutions for engineering problems and use this knowledge to acquire higher
education
2. Core Competence
To train the students in chemistry practicals so that they apply their knowledge and training to compare,
and to analyze various engineering industrial problems to find solutions
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice this enables
them to find solutions for the real time problems in industry, and to design products
4. Professionalism
To inculcate professional and effective communication skills, leadership qualities and team spirit in the
students to make them multi-faceted personalities and develop their ability to relate engineering issues to
broader social context
5. Lifelong Learning/Ethics
To demonstrate and practice ethical and professional responsibilities in the industry and society in the
large, through commitment and lifelong learning needed for successful professional career






4


PROGRAMME OUTCOMES (POs)
To demonstrate and apply knowledge of Mathematics, Science and engineering fundamentals in the following
experiments.
1 .To estimate HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. To determine total, temporary & permanent hardness of water by EDTA method.
3. To determine DO content of water sample by Winkler?s method.
4. To determine chloride content of water sample by Argentometric method.
5. To estimate copper content of the given solution by Iodometry.
6. To determine strength of given hydrochloric acid using pH meter.
7. To determine strength of acids in a mixture of acids using conductivity meter.
8. To determine iron content of the given solution using potentiometer.
9. To estimate iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. To estimate sodium and potassium present in water using flame photometer.
11. To determine molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. To determine Pseudo first order kinetics ? ester hydrolysis.
13. To determine Corrosion experiment ? weight loss method.
14. To estimate CMC.
15. To estimate Phase change in a solid.
16. To determine strength of strong acid vs strong base using conductivity meter.











5

BS8161 - CHEMISTRY LABORATORY
SYLLABUS


? To make the student to acquire practical skills in the determination of water quality
parameters through volumetric and instrumental analysis.

? ???? ??? ???? ?? ???? ? ? ?To acquaint the students with the determination of molecular weight of a polymer by
viscometery.

LIST OF EXPERIMENTS:
1. Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. Determination of total, temporary & permanent hardness of water by EDTA method.
3. Determination of DO content of water sample by Winkler?s method.
4. Determination of chloride content of water sample by Argentometric method.
5. Estimation of copper content of the given solution by Iodometry.
6. Determination of strength of given hydrochloric acid using pH meter.
7. Determination of strength of acids in a mixture of acids using conductivity meter.
8. Estimation of iron content of the given solution using potentiometer.
9. Estimation of iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. Estimation of sodium and potassium present in water using flame photometer.
11. Determination of molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. Pseudo first order kinetics ? ester hydrolysis.
13. Corrosion experiment ? weight loss method.
14. Determination of CMC.
15. Phase change in a solid.
16. Conductometric titration of strong acid vs strong base.




? The students will be outfitted with hands-on knowledge in the quantitative chemical
analysis of water quality related parameters.
COURSE OBJECTIVES
COURSE OUTCOMES
6


INDEX [ SEMESTER ? I ]


S.No.



Date


Experiment

Date of
submission



Mark


Signature

1.

Estimation of HCl using Na 2CO 3 as
primary standard and Determination of
alkalinity in water sample.



2.


Determination of total, temporary &
permanent hardness of water by EDTA
method.



3.


Determination of chloride content of water
sample by argentometric method.



4.


Determination of strength of given
hydrochloric acid using pH meter.



5.


Determination of strength of acids in a
mixture of acids using conductivity meter.



6.


Estimation of iron content of the given
solution using potentiometer.



7.





Conductometric titration of strong acid Vs
strong base.



8.



Estimation of copper content of the given
solution by Iodometry


9.
Estimation of sodium and potassium
present in water using flame photometer




7




CONTENTS


S.No.


NAME OF EXPERIMENT

PAGE
No.
SEMESTER - I
1.
Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in
water sample.
09
2. Determination of total, temporary & permanent hardness of water by EDTA method. 15
3. Determination of chloride content of water sample by Argentometric method. 21
4. Determination of strength of given hydrochloric acid using pH meter. 25
5. Determination of strength of acids in a mixture of acids using conductivity meter. 29
6. Estimation of iron content of the given solution using potentiometer. 33
7. Conductometric titration of strong acid Vs strong base.

39


42

8


Estimation of copper content of the given solution by Iodometry 43
9 Estimation of sodium and potassium present in water using flame photometer 47






8



SHORT PROCEDURE:

CONTENTS
TITRATION
Estimation of alkalinity in water sample
(Std HCl Vs water sample)

Burette solution

Std. HCl


Pipette solution

Water sample


Indicator


(i) Phenolphthalein
(ii) Methyl orange


End point

(i) Disappearance of pink colour
(ii) Appearance of reddish orange colour






Relationship
between P &M
Nature of alkalinity
Amount of individual
alkalinities
OH
-
HCO 3
-


CO 3
2-

P = M

only OH
-

P or M

?
0.0

0.0


2P = M

only CO 3
2-


2P or M


0.0


0.0


?

P =0, M?0

only HCO 3
-



M



0.0



?

0.0


2P > M


OH
-
&CO 3
2-


OH
-
= 2P-M
CO 3
2-
= 2(M-P)


?

0.0

?

P < ? M




HCO 3
-
&CO 3
2-


HCO 3
-
= M-2P
CO 3
2-
= 2P

0.0 ? ?




9





Expt. No. 1 DETERMINATION OF ALKALINITY IN WATER
AIM
To determine the type and amounts of alkalinity in the given water sample. A standard solution of Na 2CO 3
of strength ____N is given.

PRINCIPLE
Alkalinity in water is due to the presence of soluble hydroxides, bicarbonates and carbonates.
Determination of various types and amounts of alkalinity is easily carried out by titration with standard HCl
employing the indicators phenolphthalein and methyl orange independently or in succession.

The following reactions occur when different types of alkalinity are neutralized with acid.

OH
?
+ H
+
? H 2O completed at pH 8.2-9.0 ----- (1)

CO 3
2 ?
+ H
+
? HCO 3
?
----- (2)

HCO 3
?
+ H
+
? (H 2CO 3) ? H 2O + CO 2, completed at pH 4.2-5.5 ----- (3)

Neutralisation (1) & (2) will be notified by phenolphthalein end-point while all the three will be

accounted by
methyl orange end-point. Bicarbonate in eqn. (3) may be due to the existence of soluble free bicarbonate salts and
bicarbonates resulting from half neutralization of soluble carbonates (eqn. (2))

Various steps to be followed

a) A known volume of water sample is titrated against std. HCl using first phenolphthalein indicator till
end-point (P) and the titration is continued without break using methyl orange indicator till the end-
point (M).



10


Titration

Estimation of Alkalinity in water sample

Standard HCl Vs Water sample Indicator: 1. Phenolphthalein
2. Methyl Orange


S.No.
Volume
of water
sample (ml)
Burette Reading
Concordant value

Initial Phenolphthalein End
Point (P)
Methyl Orange End
Point (M)

1

2






CALCULATION

Hydroxide ion alkalinity
Volume of HCl (2P-M) = ???????ml

Strength of HCl = ???????? N

Volume of water sample = ???????...ml

Strength of water sample = Volume of HCl (2P-M) x Strength of HCl
Volume of water sample

=

? Hydroxide ion alkalinity in terms of
CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ??????.mg/l







11




b) From the magnitudes of the P & M, the nature of alkalinity can be arrived as follows:

(i) P = M => Presence of only OH
-

(ii) 2P = M => Presence of only CO 3
2-

(iii) P =0, M=0 => Presence of only HCO 3
-
(iv) 2P > M => Presence of OH
-
& CO 3
2-
(v) 2P < M => Presence of HCO 3
-
& CO 3
2-

(Mixture of OH
-
& HCO3
-
is not listed since they do not exist together and are considered equivalent to CO 3
2-
).

PROCEDURE
TITRATION
ESTIMATION OF ALKALINITY IN WATER SAMPLE

Exactly 20 ml of water sample is pipetted out into a clean conical flask. Few drops of phenolphthalein
indicator are added and titrated against a standardized HCl taken in the burette. The end point is the
disappearance of pink colour, which is noted as P. Few drops of methyl orange indicator is added to the same
solution. The solution turns to yellow. The titration is continued further by adding same HCl without break till the
end point is reached. The end point is the colour change from yellow to reddish orange.

The experiment is repeated to get concordant values. From the magnitudes of P & M values, the type of
alkalinity present in the water sample is inferred and the individual amounts are calculated and reported.










12


Carbonate ion alkalinity

Volume of HCl 2 (M ? P) = ??? ????????ml

Strength of HCl = ??.?????..???...N

Volume of water sample =........................................ml

Strength of water sample = Volume of HCl 2 (M ? P) x Strength of HCl
Volume of water sample

= ???????????.. N




? Carbonate ion alkalinity
in terms of CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ???????????mg/l

















13





RESULT

1) The type of alkalinity present in the water sample = -------------------------ions.

2) The individual amounts of alkalinity present in the water sample:
Hydroxide ion alkalinity

= ----------------- ppm
Carbonate ion alkalinity = ------------------ ppm
Bicarbonate ion alkalinity = ----------------- ppm





VIVA-VOCE


1. What is meant by alkalinity?
2. What are the ions responsible for alkalinity?
3. Why OH
-
and HCO 3
?
ions cannot exist together in water?
4. What are the ions responsible for alkalinity when 2P > M?
5. What is the pH range for both in acidic and basic solutions?
6. What is the colour of phenolphthalein in an acid and in an alkaline solution?
7. What is the purpose of using two indicators in same titration?
8. What are the possible combinations of ions for alkalinity?
9. How is the amount of alkalinity expressed?
10. What are the types of indicator used in this experiment?







14

SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II TITRATION III
Standardisation of
EDTA
(EDTA Vs Std
Hard water)
Determination of
total hardness
(Std EDTA Vs Hard
water sample)
Determination of
permanent hardness
(Std EDTA Vs Boiled
Hard water sample)

Burette solution

EDTA solution

EDTA solution

EDTA solution

Pipette solution

20ml Std. hard water

20 ml hard water sample

20ml boiled hard water sample

Indicator

2 drops of EBT

2 drops of EBT

2 drops of EBT

Additional soln.


Ammoniacal Buffer
solution (5ml)

Ammoniacal Buffer solution
(5ml)

Ammoniacal Buffer solution
(5ml)
End point Wine - red to Steel blue Wine - red to steel blue Wine - red to Steel blue




STANDARDISATION OF EDTA
Titration - I
Std. HARD WATER Vs EDTA Indicator: EBT

S. No.
Volume of std hard
water (ml)
Burette Reading Volume of
EDTA
(V 1) (ml)
Concordant value

Initial

Final



Volume of std .hard water taken = 20 ml
Volume of EDTA consumed (V 1) = --------------- ml
1 ml of std.hard water = 1mg of CaCO 3
20 ml of std hard water = 20 mg of CaCO 3

V 1 ml of EDTA solution containing 20 mg of CaCO 3
1 ml of EDTA solution = 20 / V 1 mg of CaCO 3
= -----------------------mg of CaCO 3


15

Expt. No. 2 DETERMINATION OF TOTAL, TEMPORARY AND
PERMANENT HARDNESS OF WATER

AIM
To estimate the amount of total, temporary & permanent hardness in the given sample of water.

PRINCIPLE
The estimation is based on the complexometric titration.

(i) Total hardness of water is estimated by titrating against EDTA using EBT indicator.
EBT+M ?[EBT-M] (unstable complex)
(EBT-M) (Unstable complex) +EDTA ? [EDTA-M] (stable complex) +EBT
EBT indicator forms wine- red colored complex with metal ions present in water. On addition of EDTA
metal ions preferably forms complexes with EDTA and steel blue EBT indicator is set free. Therefore
change of colour from wine- red to steel blue denotes the end point.

(ii) Temporary hardness is removed by boiling the water.
Ca (HCO 3) 2 ? CaCO 3 +CO 2 ?+H 2O
Mg (HCO 3) 2 ? Mg(OH) 2 +2CO 2 ?
The precipitate is filtered and the remaining permanent hardness is estimated using EDTA.

PROCEDURE

TITRATION ? I
STANDARDISATION OF EDTA

Pipette out 20ml of standard hard water into a 250ml conical flask. Add 5ml of buffer solution and 3
drops of eriochrome black T indictor. Titrate the solution with EDTA from the burette until the colour
changes from wine- red to steel blue at the end point. Repeat the titration for concordant values. Let the
titre value be V 1ml.


16


Titration-II
SAMPLE HARD WATER Vs Std EDTA Indicator: EBT

S.No. Volume of sample
hard water (ml)
Burette Reading Volume of
EDTA
(V 2) (ml)
Concordant value

Initial

Final




CALCULATION

Calculation of total hardness


Volume of EDTA consumed (V 2) = ------------------------- ml
1ml of EDTA = 20 / V 1 mg of CaCO 3
V 2 ml of EDTA = 20 / V 1 x V 2 mg of CaCO 3

( i.e), If 20ml of sample hard water contains 20 x V 2 mg of CaCO 3 / V 1

Then 1000ml of water sample = 20 x V 2 x 1000 / V 1 x 20 mg of CaCO 3

= 1000 x V 2 / V 1 mg of CaCO3

Total hardness of given water sample = ---------------------ppm









17



DETERMINATION OF TOTAL HARDNESS

Pipette out 20ml of sample hard water into a clean conical flask. Add 5ml of buffer solution and 4 -5
drops of Eriochrome black -T indicator. Titrate the wine - red coloured solution with EDTA from the burette until
the colour steel blue appears at the end point. Repeat the titration for concordant values. Let the titre value be
V 2ml.



DETERMINATION OF PERMANENT HARDNESS

Take 100ml of hard water sample in a 500ml beaker and boil gently for about 1hour. Cool, filter it into a
100ml standard flask and make the volume up to the mark. Take 20ml of this solution and proceed it in the same
way as in titration (I). The volume of EDTA consumed corresponds to the permanent hardness of the water
sample. Let the titre value be V 3ml. Temporary hardness is calculated by subtracting permanent hardness from
total hardness.





















18




DETERMINATION OF PERMANENT HARDNESS
BOILED SAMPLE WATER Vs Std. EDTA Indicator: EBT


S.No.
Volume of boiled
hard water (ml)
Burette Reading (ml) Volume of
EDTA
(ml)

Concordant value

Initial Final



CALCULATION OF PERMANENT HARDNESS


Volume of EDTA consumed V 3 = ---------------------ml

1ml of EDTA = 20 / V 1 mg of CaCO 3

V 3ml of EDTA = 20 / V 1 x V 3 mg of CaCO 3

(i.e) 20 ml of boiled sample hard water = 20 / V 1 x V 3 mg of CaCO 3

Then 1000ml of boiled water sample = 20 / V 1 x V 3 / 20 * 1000mg of CaCO 3

= 1000 x V 3 / V 1 mg of CaCO 3

permanent hardness of boiled water sample = -----------------ppm

Temporary hardness of the given water sample = Total hardness ? Permanent hardness

= ------------------ppm

19







RESULT

(i) Total hardness of the given sample water = -------------- ppm.
(ii) Permanent hardness of the given sample water = --------------- ppm.
(iii) Temporary hardness of the given sample water = ----------------ppm.







VIVA-VOCE

1. Define ? Hard water
2. What is the structure of EDTA?
3. How will you calculate temporary hardness?
4. What is the role of the buffer in EDTA titration?
5. What is the permissible limit of hardness in drinking water?
6. Name the hardness producing ions present in water.
7. Name two salts which are responsible for temporary hardness.
8. Why is CaCO 3 taken as the standard?
9. Write the expansion of EDTA.
10. What is meant by EBT?











20





SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II
Standardisation of
AgNO 3
Estimation of Chloride
Burette solution

AgNO 3 solution

Std. AgNO 3 solution

Pipette solution

20ml std KCl solution

20 ml water sample

Indicator

1ml K 2CrO 4

1ml K 2CrO 4


End point

yellow to reddish brown

yellow to reddish brown

Titration I
Std. AgNO3 Vs KCl Indicator: Potassium Chromate













CALCULATION

Volume of KCl (V 1) = ------- ml

Strength of KCl (N 1) = ------- N

Volume of Silver Nitrate (V 2) = -------- ml

Strength of Siver Nitrate V 1N 1
N 2 =
V 1

= --------------------- N

S.No.
Volume of KCl
(ml)
Burette Reading (ml)
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

21




Expt.No. 3 ESTIMATION OF CHLORIDE CONTENT IN WATER
(ARGENTOMETRIC METHOD)
AIM
To estimate the amount of chloride present in given water sample by Argentometric method (Mohr?s
method). You are provided with standard solution of NaCl of strength --------N and a approximately N/10 solution of
Silver nitrate.

PRINCIPLE
The Chloride ion in the form of NaCl, KCl, CaCl 2, MgCl 2 etc., present in the water sample can be estimated
by Argentometric method or known as Mohr?s method. It is an example for precipitation titration. The reaction
between std. Sodium chloride and Silver nitrate is given below.
AgNO 3 + NaCl ? AgCl ? + NaNO 3
The completion of reaction can be observed by employing potassium chromate as the indicator. The end
point is the colour change from yellow to reddish brown due to the following reaction.
2AgNO 3 + K 2CrO 4 ? Ag 2CrO 4 ? + 2KNO 3
Potassium chromate indicator will not be precipitated as silver chromate until all the chlorides in the solution
have been precipitated as AgCl Since a precipitation reaction takes place in preference, this reaction takes place
only at the end point.

PROCEDURE
TITRATION I: STANDARDISATION OF SILVER NITRATE
Pipette out 20ml of standard sodium or potassium chloride solution into a clean conical flask. Add 1ml of 5%
K 2CrO 4 indicator, as the solution turns yellow in colour. Titrate it against silver nitrate solution taken in the burette.
Observe the nearness of the end point through the formation of coagulated silver chloride precipitate at the bottom
of the flask. Now add the silver nitrate drop by drop until the solution gets a faint reddish brown tinge. Repeat the
titration for concordant value. Let the volume of silver nitrate be V 2ml.





22






TITRATION - II

Std AgNO3 Vs WATER SAMPLE Indicator: Potassium Chromate













CALCULATION

Volume of Silver Nitrate (V 3) = ------------ ml

Strength of Siver Nitrate (N 3) = ------------- N

Volume of Water sample (V 4) = -------------- ml

Strength of Water sample V 3 N 3
(N 4) =
V 4

= ----------------- N

Amount of Chloride ion present in 1000 ml of the water sample = Equivalent mass of HCl X 1000


= N 4 x 35.46 x 1000


= -----------------mg/l







S.No.
Volume of water
sample (ml)
Burette Reading
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

23





TITRATION - II
ESTIMATION OF CHLORIDE ION

Pipette out 40 ml of the given water sample into a clean conical flask.To this sample add 1ml of 5% K 2CrO 4
indicator and titrate it against the standardized silver nitrate solution taken in the burette and continue the titration
until the solution produces a reddish brown colour. Note down the end point and repeat the titration for
concordance. Let the volume be V 3ml.







RESULT

The amount of chloride ion present in the water sample = ----------------- mg/l.




VIVA-VOCE

1. Why is this method known as Argentometric method?
2.
What is the chemical reaction between AgNO 3 and Cl
-
ions present in water?

3.
What is the form of Chloride ion present in water?

4. What is the reaction between AgNO 3 and K 2CrO 4 ?
5. What is the name of the method used in this titration?
6. Name the link solution used in the determination.
7. Name the solution used to standardize AgNO 3.
8. What is the indicator used in the determination?
9. How will you calculate the amount of chloride ion in the given solution?
10. What is the colour change in the titration?




24




SHORT PROCEDURE


CONTENTS

TITRATION I

TITRATION II
Burette solution

Std Sodium Hydroxide

Std Sodium Hydroxide

Pipette solution

20 ml hydrochloric acid 20 ml hydrochloric acid
Additional solution


20 ml distilled water

20 ml distilled water


End point



Sudden increase in pH
pH gradual increase

Equivalent Weight of HCl = 36.5







ROUGH GRAPH FAIR GRAPH











pH
? pH/ ? V





Volume of NaOH
(ml)
Volume of NaOH
(ml)





25



Expt. No. 4 DETERMINATION OF STRENGTH OF HCl by pH METRY

AIM
To determine the strength of given HCl by pH metry. A standard solution of 0.1N NaOH is provided.

PRINCIPLE
The pH of a solution is related to H
+
ion concentration by the following formula.

. pH = -log [ H
+
]

pH of a solution is indirectly related to H
+
ion concentration. When NaOH is added slowly to HCl, H
+
ions
get neutralized by OH
-
ions. The pH increases slowly.

H
+
+ Cl
-
+ Na
+
+ OH
-
? Na
+
+ Cl
-
+H 2O

When all H
+
ions of HCl are neutralized at the end point, addition of NaOH causes high increase in pH
because of the addition of excess OH
-
ions.

MATERIALS REQUIRED
pH meter, Glass electrode, Burette, Pipette, Std.NaOH, approximately N/10 HCl .

PROCEDURE

The burette is washed with distilled water, rinsed with the given std. Sodium hydroxide and filled with the
same solution. Exactly 10ml of the given HCl solution is pipetted out into a clean beaker. It is then diluted to 50ml
with distilled water. A glass electrode is dipped into the solution and its terminals are connected to a pH meter.

26

TITRATION - I
S.No Volume of
NaOH (ml)
pH
1

2

3

4

5

6

7

8

9

10


TITRATION - II



CALCULATION

Volume of NaOH (V 1) = ------------------- ml ( titre value)
Strength of NaOH (N 1) = ------------------- N
Volume of HCl (V 2) = ------------------ml
Strength of HCl (N 2) = ------------------ N
N 2 = V 1 N 1 / V 2
Strength of HCl = -------------------- N
Amount of HCl present in 1000ml of the given solution = Strength x equivalent weight of HCl
= ------------------ X 36.5
= --------------------- g
S.No Volume of
NaOH (ml)
pH
11

12

13

14

15

16

17

18

19

20

S.No
Volume of
NaOH (ml)
pH ?pH ?V ?pH / ?V
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
27



Now NaOH is gradually added from the burette to HCl taken in the beaker. pH of the solution is noted for
each addition of NaOH. This process is continued until 5 readings are taken after the end point.
A fair titration is performed to find the exact end point.





RESULT

(i) Strength of the given HCl solution = ---------------- N
(ii) Amount of HCl present in a litre of the solution = ---------------- g


VIVA-VOCE

1. What is meant by pH?
2. What is the name of the reference electrode used ?
3. Why does pH value increase suddenly at the end point?
4. What is the indicator used in the titration?
5. What is the pH range of human blood?
6. What is the unit of pH?
7. How will you calculate the amount of HCl?
8. How is glass electrode represented?
9. Why is glass electrode known as ion selective electrode?
10. What is the chemical reaction involved in this titration?





28




SHORT PROCEDURE


CONTENTS
TITRATION
Burette solution

Std Sodium Hydroxide

Pipette solution

20 ml mixture of acid (HCl+ CH 3COOH)


Additional solution

20 ml distilled water


End point

Conductivity decreases-slowly increases-Sudden increase



Equivalent Weight of HCl = 36.5


Equivalent Weight of CH 3COOH = 60



MODEL GRAPH


Conductance
Volume of NaOH
Mixture of Acids






29




Expt. No. 5 CONDUCTOMETRIC TITRATION OF MIXTURE
OF ACIDS

AIM
To determine the amount of a strong acid and a weak acid present in the given solution.

PRINCIPLE

Solution of electrolytes conducts electricity due to the presence of ions. Since specific conductance of a
solution is proportional to the concentration of ions in it, conductance of the solution is measured during the titration.

HCl + NaOH ? NaCl + H 2O (I neutralization)

CH 3COOH + NaOH ? CH 3COONa + H 2O (II neutralization)

When a solution of HCl is treated with NaOH the fast moving hydrogen ions are progressively replaced by
slow moving sodium ions. As a result conductance of the solution decreases. This decrease will take place until the
first neutralisation point is reached. Further addition of alkali results in formation of sodium acetate.

Since sodium acetate is stronger than acetic acid conductivity slowly increases until all acetic acid is
completely neutralized.(II Neutralisation) This is due to the presence of fast moving OH
-
ions. Anymore addition of
alkali increases the conductance sharply.

PROCEDURE
The burette is filled with NaOH solution upto zero mark. The given unknown solution (mixture of a weak &
a strong acid) is transferred into a 100ml standard flask and made upto the mark with distilled water. 20ml of the
made up solution is pipetted out into a clean 100ml beaker. The solution is diluted to 20ml using distilled water. A
conductivity cell is dipped into the solution and the terminals are connected to a conductivity meter.
30


TITRATION


CALCULATION OF STRENGTH OF HCl
Volume of NaOH (V 1) = --------------- ml (titre value)
Strength of NaOH (N 1) = ---------------- N
Volume of HCl (V 2) = ------------ ml
Strength of HCl (N 2) = -------------- N

N 2 = V 1 N 1 / V 2
Strength of HCl = ---------------- N
CALCULATION OF STRENGTH OF CH3COOH
Volume of NaOH (V 1) = ------------ ml (titre value)
Strength of NaOH (N 1) = ------------ N
Volume of CH 3COOH (V 2) = ------------ ml
Strength of CH 3COOH (N 2) = ------------ N
N 2 = V 1 N 1 / V 2

Strength of CH 3COOH = ------------ N



S.No

Volume of NaOH
(ml)

Conductance (mho)

14

15

16

17
18
19
20

21
22
23
24
25
26

S.No

Volume of NaOH
(ml)

Conductance (mho)

1
2
3
4
5
6
7
8
9
10
11
12
13
FirstRanker.com - FirstRanker's Choice



?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





3


PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)
1. Fundamentals
To provide students with a solid foundation in Mathematics, Science and fundamentals of engineering,
enabling them to apply, to find solutions for engineering problems and use this knowledge to acquire higher
education
2. Core Competence
To train the students in chemistry practicals so that they apply their knowledge and training to compare,
and to analyze various engineering industrial problems to find solutions
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice this enables
them to find solutions for the real time problems in industry, and to design products
4. Professionalism
To inculcate professional and effective communication skills, leadership qualities and team spirit in the
students to make them multi-faceted personalities and develop their ability to relate engineering issues to
broader social context
5. Lifelong Learning/Ethics
To demonstrate and practice ethical and professional responsibilities in the industry and society in the
large, through commitment and lifelong learning needed for successful professional career






4


PROGRAMME OUTCOMES (POs)
To demonstrate and apply knowledge of Mathematics, Science and engineering fundamentals in the following
experiments.
1 .To estimate HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. To determine total, temporary & permanent hardness of water by EDTA method.
3. To determine DO content of water sample by Winkler?s method.
4. To determine chloride content of water sample by Argentometric method.
5. To estimate copper content of the given solution by Iodometry.
6. To determine strength of given hydrochloric acid using pH meter.
7. To determine strength of acids in a mixture of acids using conductivity meter.
8. To determine iron content of the given solution using potentiometer.
9. To estimate iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. To estimate sodium and potassium present in water using flame photometer.
11. To determine molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. To determine Pseudo first order kinetics ? ester hydrolysis.
13. To determine Corrosion experiment ? weight loss method.
14. To estimate CMC.
15. To estimate Phase change in a solid.
16. To determine strength of strong acid vs strong base using conductivity meter.











5

BS8161 - CHEMISTRY LABORATORY
SYLLABUS


? To make the student to acquire practical skills in the determination of water quality
parameters through volumetric and instrumental analysis.

? ???? ??? ???? ?? ???? ? ? ?To acquaint the students with the determination of molecular weight of a polymer by
viscometery.

LIST OF EXPERIMENTS:
1. Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. Determination of total, temporary & permanent hardness of water by EDTA method.
3. Determination of DO content of water sample by Winkler?s method.
4. Determination of chloride content of water sample by Argentometric method.
5. Estimation of copper content of the given solution by Iodometry.
6. Determination of strength of given hydrochloric acid using pH meter.
7. Determination of strength of acids in a mixture of acids using conductivity meter.
8. Estimation of iron content of the given solution using potentiometer.
9. Estimation of iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. Estimation of sodium and potassium present in water using flame photometer.
11. Determination of molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. Pseudo first order kinetics ? ester hydrolysis.
13. Corrosion experiment ? weight loss method.
14. Determination of CMC.
15. Phase change in a solid.
16. Conductometric titration of strong acid vs strong base.




? The students will be outfitted with hands-on knowledge in the quantitative chemical
analysis of water quality related parameters.
COURSE OBJECTIVES
COURSE OUTCOMES
6


INDEX [ SEMESTER ? I ]


S.No.



Date


Experiment

Date of
submission



Mark


Signature

1.

Estimation of HCl using Na 2CO 3 as
primary standard and Determination of
alkalinity in water sample.



2.


Determination of total, temporary &
permanent hardness of water by EDTA
method.



3.


Determination of chloride content of water
sample by argentometric method.



4.


Determination of strength of given
hydrochloric acid using pH meter.



5.


Determination of strength of acids in a
mixture of acids using conductivity meter.



6.


Estimation of iron content of the given
solution using potentiometer.



7.





Conductometric titration of strong acid Vs
strong base.



8.



Estimation of copper content of the given
solution by Iodometry


9.
Estimation of sodium and potassium
present in water using flame photometer




7




CONTENTS


S.No.


NAME OF EXPERIMENT

PAGE
No.
SEMESTER - I
1.
Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in
water sample.
09
2. Determination of total, temporary & permanent hardness of water by EDTA method. 15
3. Determination of chloride content of water sample by Argentometric method. 21
4. Determination of strength of given hydrochloric acid using pH meter. 25
5. Determination of strength of acids in a mixture of acids using conductivity meter. 29
6. Estimation of iron content of the given solution using potentiometer. 33
7. Conductometric titration of strong acid Vs strong base.

39


42

8


Estimation of copper content of the given solution by Iodometry 43
9 Estimation of sodium and potassium present in water using flame photometer 47






8



SHORT PROCEDURE:

CONTENTS
TITRATION
Estimation of alkalinity in water sample
(Std HCl Vs water sample)

Burette solution

Std. HCl


Pipette solution

Water sample


Indicator


(i) Phenolphthalein
(ii) Methyl orange


End point

(i) Disappearance of pink colour
(ii) Appearance of reddish orange colour






Relationship
between P &M
Nature of alkalinity
Amount of individual
alkalinities
OH
-
HCO 3
-


CO 3
2-

P = M

only OH
-

P or M

?
0.0

0.0


2P = M

only CO 3
2-


2P or M


0.0


0.0


?

P =0, M?0

only HCO 3
-



M



0.0



?

0.0


2P > M


OH
-
&CO 3
2-


OH
-
= 2P-M
CO 3
2-
= 2(M-P)


?

0.0

?

P < ? M




HCO 3
-
&CO 3
2-


HCO 3
-
= M-2P
CO 3
2-
= 2P

0.0 ? ?




9





Expt. No. 1 DETERMINATION OF ALKALINITY IN WATER
AIM
To determine the type and amounts of alkalinity in the given water sample. A standard solution of Na 2CO 3
of strength ____N is given.

PRINCIPLE
Alkalinity in water is due to the presence of soluble hydroxides, bicarbonates and carbonates.
Determination of various types and amounts of alkalinity is easily carried out by titration with standard HCl
employing the indicators phenolphthalein and methyl orange independently or in succession.

The following reactions occur when different types of alkalinity are neutralized with acid.

OH
?
+ H
+
? H 2O completed at pH 8.2-9.0 ----- (1)

CO 3
2 ?
+ H
+
? HCO 3
?
----- (2)

HCO 3
?
+ H
+
? (H 2CO 3) ? H 2O + CO 2, completed at pH 4.2-5.5 ----- (3)

Neutralisation (1) & (2) will be notified by phenolphthalein end-point while all the three will be

accounted by
methyl orange end-point. Bicarbonate in eqn. (3) may be due to the existence of soluble free bicarbonate salts and
bicarbonates resulting from half neutralization of soluble carbonates (eqn. (2))

Various steps to be followed

a) A known volume of water sample is titrated against std. HCl using first phenolphthalein indicator till
end-point (P) and the titration is continued without break using methyl orange indicator till the end-
point (M).



10


Titration

Estimation of Alkalinity in water sample

Standard HCl Vs Water sample Indicator: 1. Phenolphthalein
2. Methyl Orange


S.No.
Volume
of water
sample (ml)
Burette Reading
Concordant value

Initial Phenolphthalein End
Point (P)
Methyl Orange End
Point (M)

1

2






CALCULATION

Hydroxide ion alkalinity
Volume of HCl (2P-M) = ???????ml

Strength of HCl = ???????? N

Volume of water sample = ???????...ml

Strength of water sample = Volume of HCl (2P-M) x Strength of HCl
Volume of water sample

=

? Hydroxide ion alkalinity in terms of
CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ??????.mg/l







11




b) From the magnitudes of the P & M, the nature of alkalinity can be arrived as follows:

(i) P = M => Presence of only OH
-

(ii) 2P = M => Presence of only CO 3
2-

(iii) P =0, M=0 => Presence of only HCO 3
-
(iv) 2P > M => Presence of OH
-
& CO 3
2-
(v) 2P < M => Presence of HCO 3
-
& CO 3
2-

(Mixture of OH
-
& HCO3
-
is not listed since they do not exist together and are considered equivalent to CO 3
2-
).

PROCEDURE
TITRATION
ESTIMATION OF ALKALINITY IN WATER SAMPLE

Exactly 20 ml of water sample is pipetted out into a clean conical flask. Few drops of phenolphthalein
indicator are added and titrated against a standardized HCl taken in the burette. The end point is the
disappearance of pink colour, which is noted as P. Few drops of methyl orange indicator is added to the same
solution. The solution turns to yellow. The titration is continued further by adding same HCl without break till the
end point is reached. The end point is the colour change from yellow to reddish orange.

The experiment is repeated to get concordant values. From the magnitudes of P & M values, the type of
alkalinity present in the water sample is inferred and the individual amounts are calculated and reported.










12


Carbonate ion alkalinity

Volume of HCl 2 (M ? P) = ??? ????????ml

Strength of HCl = ??.?????..???...N

Volume of water sample =........................................ml

Strength of water sample = Volume of HCl 2 (M ? P) x Strength of HCl
Volume of water sample

= ???????????.. N




? Carbonate ion alkalinity
in terms of CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ???????????mg/l

















13





RESULT

1) The type of alkalinity present in the water sample = -------------------------ions.

2) The individual amounts of alkalinity present in the water sample:
Hydroxide ion alkalinity

= ----------------- ppm
Carbonate ion alkalinity = ------------------ ppm
Bicarbonate ion alkalinity = ----------------- ppm





VIVA-VOCE


1. What is meant by alkalinity?
2. What are the ions responsible for alkalinity?
3. Why OH
-
and HCO 3
?
ions cannot exist together in water?
4. What are the ions responsible for alkalinity when 2P > M?
5. What is the pH range for both in acidic and basic solutions?
6. What is the colour of phenolphthalein in an acid and in an alkaline solution?
7. What is the purpose of using two indicators in same titration?
8. What are the possible combinations of ions for alkalinity?
9. How is the amount of alkalinity expressed?
10. What are the types of indicator used in this experiment?







14

SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II TITRATION III
Standardisation of
EDTA
(EDTA Vs Std
Hard water)
Determination of
total hardness
(Std EDTA Vs Hard
water sample)
Determination of
permanent hardness
(Std EDTA Vs Boiled
Hard water sample)

Burette solution

EDTA solution

EDTA solution

EDTA solution

Pipette solution

20ml Std. hard water

20 ml hard water sample

20ml boiled hard water sample

Indicator

2 drops of EBT

2 drops of EBT

2 drops of EBT

Additional soln.


Ammoniacal Buffer
solution (5ml)

Ammoniacal Buffer solution
(5ml)

Ammoniacal Buffer solution
(5ml)
End point Wine - red to Steel blue Wine - red to steel blue Wine - red to Steel blue




STANDARDISATION OF EDTA
Titration - I
Std. HARD WATER Vs EDTA Indicator: EBT

S. No.
Volume of std hard
water (ml)
Burette Reading Volume of
EDTA
(V 1) (ml)
Concordant value

Initial

Final



Volume of std .hard water taken = 20 ml
Volume of EDTA consumed (V 1) = --------------- ml
1 ml of std.hard water = 1mg of CaCO 3
20 ml of std hard water = 20 mg of CaCO 3

V 1 ml of EDTA solution containing 20 mg of CaCO 3
1 ml of EDTA solution = 20 / V 1 mg of CaCO 3
= -----------------------mg of CaCO 3


15

Expt. No. 2 DETERMINATION OF TOTAL, TEMPORARY AND
PERMANENT HARDNESS OF WATER

AIM
To estimate the amount of total, temporary & permanent hardness in the given sample of water.

PRINCIPLE
The estimation is based on the complexometric titration.

(i) Total hardness of water is estimated by titrating against EDTA using EBT indicator.
EBT+M ?[EBT-M] (unstable complex)
(EBT-M) (Unstable complex) +EDTA ? [EDTA-M] (stable complex) +EBT
EBT indicator forms wine- red colored complex with metal ions present in water. On addition of EDTA
metal ions preferably forms complexes with EDTA and steel blue EBT indicator is set free. Therefore
change of colour from wine- red to steel blue denotes the end point.

(ii) Temporary hardness is removed by boiling the water.
Ca (HCO 3) 2 ? CaCO 3 +CO 2 ?+H 2O
Mg (HCO 3) 2 ? Mg(OH) 2 +2CO 2 ?
The precipitate is filtered and the remaining permanent hardness is estimated using EDTA.

PROCEDURE

TITRATION ? I
STANDARDISATION OF EDTA

Pipette out 20ml of standard hard water into a 250ml conical flask. Add 5ml of buffer solution and 3
drops of eriochrome black T indictor. Titrate the solution with EDTA from the burette until the colour
changes from wine- red to steel blue at the end point. Repeat the titration for concordant values. Let the
titre value be V 1ml.


16


Titration-II
SAMPLE HARD WATER Vs Std EDTA Indicator: EBT

S.No. Volume of sample
hard water (ml)
Burette Reading Volume of
EDTA
(V 2) (ml)
Concordant value

Initial

Final




CALCULATION

Calculation of total hardness


Volume of EDTA consumed (V 2) = ------------------------- ml
1ml of EDTA = 20 / V 1 mg of CaCO 3
V 2 ml of EDTA = 20 / V 1 x V 2 mg of CaCO 3

( i.e), If 20ml of sample hard water contains 20 x V 2 mg of CaCO 3 / V 1

Then 1000ml of water sample = 20 x V 2 x 1000 / V 1 x 20 mg of CaCO 3

= 1000 x V 2 / V 1 mg of CaCO3

Total hardness of given water sample = ---------------------ppm









17



DETERMINATION OF TOTAL HARDNESS

Pipette out 20ml of sample hard water into a clean conical flask. Add 5ml of buffer solution and 4 -5
drops of Eriochrome black -T indicator. Titrate the wine - red coloured solution with EDTA from the burette until
the colour steel blue appears at the end point. Repeat the titration for concordant values. Let the titre value be
V 2ml.



DETERMINATION OF PERMANENT HARDNESS

Take 100ml of hard water sample in a 500ml beaker and boil gently for about 1hour. Cool, filter it into a
100ml standard flask and make the volume up to the mark. Take 20ml of this solution and proceed it in the same
way as in titration (I). The volume of EDTA consumed corresponds to the permanent hardness of the water
sample. Let the titre value be V 3ml. Temporary hardness is calculated by subtracting permanent hardness from
total hardness.





















18




DETERMINATION OF PERMANENT HARDNESS
BOILED SAMPLE WATER Vs Std. EDTA Indicator: EBT


S.No.
Volume of boiled
hard water (ml)
Burette Reading (ml) Volume of
EDTA
(ml)

Concordant value

Initial Final



CALCULATION OF PERMANENT HARDNESS


Volume of EDTA consumed V 3 = ---------------------ml

1ml of EDTA = 20 / V 1 mg of CaCO 3

V 3ml of EDTA = 20 / V 1 x V 3 mg of CaCO 3

(i.e) 20 ml of boiled sample hard water = 20 / V 1 x V 3 mg of CaCO 3

Then 1000ml of boiled water sample = 20 / V 1 x V 3 / 20 * 1000mg of CaCO 3

= 1000 x V 3 / V 1 mg of CaCO 3

permanent hardness of boiled water sample = -----------------ppm

Temporary hardness of the given water sample = Total hardness ? Permanent hardness

= ------------------ppm

19







RESULT

(i) Total hardness of the given sample water = -------------- ppm.
(ii) Permanent hardness of the given sample water = --------------- ppm.
(iii) Temporary hardness of the given sample water = ----------------ppm.







VIVA-VOCE

1. Define ? Hard water
2. What is the structure of EDTA?
3. How will you calculate temporary hardness?
4. What is the role of the buffer in EDTA titration?
5. What is the permissible limit of hardness in drinking water?
6. Name the hardness producing ions present in water.
7. Name two salts which are responsible for temporary hardness.
8. Why is CaCO 3 taken as the standard?
9. Write the expansion of EDTA.
10. What is meant by EBT?











20





SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II
Standardisation of
AgNO 3
Estimation of Chloride
Burette solution

AgNO 3 solution

Std. AgNO 3 solution

Pipette solution

20ml std KCl solution

20 ml water sample

Indicator

1ml K 2CrO 4

1ml K 2CrO 4


End point

yellow to reddish brown

yellow to reddish brown

Titration I
Std. AgNO3 Vs KCl Indicator: Potassium Chromate













CALCULATION

Volume of KCl (V 1) = ------- ml

Strength of KCl (N 1) = ------- N

Volume of Silver Nitrate (V 2) = -------- ml

Strength of Siver Nitrate V 1N 1
N 2 =
V 1

= --------------------- N

S.No.
Volume of KCl
(ml)
Burette Reading (ml)
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

21




Expt.No. 3 ESTIMATION OF CHLORIDE CONTENT IN WATER
(ARGENTOMETRIC METHOD)
AIM
To estimate the amount of chloride present in given water sample by Argentometric method (Mohr?s
method). You are provided with standard solution of NaCl of strength --------N and a approximately N/10 solution of
Silver nitrate.

PRINCIPLE
The Chloride ion in the form of NaCl, KCl, CaCl 2, MgCl 2 etc., present in the water sample can be estimated
by Argentometric method or known as Mohr?s method. It is an example for precipitation titration. The reaction
between std. Sodium chloride and Silver nitrate is given below.
AgNO 3 + NaCl ? AgCl ? + NaNO 3
The completion of reaction can be observed by employing potassium chromate as the indicator. The end
point is the colour change from yellow to reddish brown due to the following reaction.
2AgNO 3 + K 2CrO 4 ? Ag 2CrO 4 ? + 2KNO 3
Potassium chromate indicator will not be precipitated as silver chromate until all the chlorides in the solution
have been precipitated as AgCl Since a precipitation reaction takes place in preference, this reaction takes place
only at the end point.

PROCEDURE
TITRATION I: STANDARDISATION OF SILVER NITRATE
Pipette out 20ml of standard sodium or potassium chloride solution into a clean conical flask. Add 1ml of 5%
K 2CrO 4 indicator, as the solution turns yellow in colour. Titrate it against silver nitrate solution taken in the burette.
Observe the nearness of the end point through the formation of coagulated silver chloride precipitate at the bottom
of the flask. Now add the silver nitrate drop by drop until the solution gets a faint reddish brown tinge. Repeat the
titration for concordant value. Let the volume of silver nitrate be V 2ml.





22






TITRATION - II

Std AgNO3 Vs WATER SAMPLE Indicator: Potassium Chromate













CALCULATION

Volume of Silver Nitrate (V 3) = ------------ ml

Strength of Siver Nitrate (N 3) = ------------- N

Volume of Water sample (V 4) = -------------- ml

Strength of Water sample V 3 N 3
(N 4) =
V 4

= ----------------- N

Amount of Chloride ion present in 1000 ml of the water sample = Equivalent mass of HCl X 1000


= N 4 x 35.46 x 1000


= -----------------mg/l







S.No.
Volume of water
sample (ml)
Burette Reading
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

23





TITRATION - II
ESTIMATION OF CHLORIDE ION

Pipette out 40 ml of the given water sample into a clean conical flask.To this sample add 1ml of 5% K 2CrO 4
indicator and titrate it against the standardized silver nitrate solution taken in the burette and continue the titration
until the solution produces a reddish brown colour. Note down the end point and repeat the titration for
concordance. Let the volume be V 3ml.







RESULT

The amount of chloride ion present in the water sample = ----------------- mg/l.




VIVA-VOCE

1. Why is this method known as Argentometric method?
2.
What is the chemical reaction between AgNO 3 and Cl
-
ions present in water?

3.
What is the form of Chloride ion present in water?

4. What is the reaction between AgNO 3 and K 2CrO 4 ?
5. What is the name of the method used in this titration?
6. Name the link solution used in the determination.
7. Name the solution used to standardize AgNO 3.
8. What is the indicator used in the determination?
9. How will you calculate the amount of chloride ion in the given solution?
10. What is the colour change in the titration?




24




SHORT PROCEDURE


CONTENTS

TITRATION I

TITRATION II
Burette solution

Std Sodium Hydroxide

Std Sodium Hydroxide

Pipette solution

20 ml hydrochloric acid 20 ml hydrochloric acid
Additional solution


20 ml distilled water

20 ml distilled water


End point



Sudden increase in pH
pH gradual increase

Equivalent Weight of HCl = 36.5







ROUGH GRAPH FAIR GRAPH











pH
? pH/ ? V





Volume of NaOH
(ml)
Volume of NaOH
(ml)





25



Expt. No. 4 DETERMINATION OF STRENGTH OF HCl by pH METRY

AIM
To determine the strength of given HCl by pH metry. A standard solution of 0.1N NaOH is provided.

PRINCIPLE
The pH of a solution is related to H
+
ion concentration by the following formula.

. pH = -log [ H
+
]

pH of a solution is indirectly related to H
+
ion concentration. When NaOH is added slowly to HCl, H
+
ions
get neutralized by OH
-
ions. The pH increases slowly.

H
+
+ Cl
-
+ Na
+
+ OH
-
? Na
+
+ Cl
-
+H 2O

When all H
+
ions of HCl are neutralized at the end point, addition of NaOH causes high increase in pH
because of the addition of excess OH
-
ions.

MATERIALS REQUIRED
pH meter, Glass electrode, Burette, Pipette, Std.NaOH, approximately N/10 HCl .

PROCEDURE

The burette is washed with distilled water, rinsed with the given std. Sodium hydroxide and filled with the
same solution. Exactly 10ml of the given HCl solution is pipetted out into a clean beaker. It is then diluted to 50ml
with distilled water. A glass electrode is dipped into the solution and its terminals are connected to a pH meter.

26

TITRATION - I
S.No Volume of
NaOH (ml)
pH
1

2

3

4

5

6

7

8

9

10


TITRATION - II



CALCULATION

Volume of NaOH (V 1) = ------------------- ml ( titre value)
Strength of NaOH (N 1) = ------------------- N
Volume of HCl (V 2) = ------------------ml
Strength of HCl (N 2) = ------------------ N
N 2 = V 1 N 1 / V 2
Strength of HCl = -------------------- N
Amount of HCl present in 1000ml of the given solution = Strength x equivalent weight of HCl
= ------------------ X 36.5
= --------------------- g
S.No Volume of
NaOH (ml)
pH
11

12

13

14

15

16

17

18

19

20

S.No
Volume of
NaOH (ml)
pH ?pH ?V ?pH / ?V
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
27



Now NaOH is gradually added from the burette to HCl taken in the beaker. pH of the solution is noted for
each addition of NaOH. This process is continued until 5 readings are taken after the end point.
A fair titration is performed to find the exact end point.





RESULT

(i) Strength of the given HCl solution = ---------------- N
(ii) Amount of HCl present in a litre of the solution = ---------------- g


VIVA-VOCE

1. What is meant by pH?
2. What is the name of the reference electrode used ?
3. Why does pH value increase suddenly at the end point?
4. What is the indicator used in the titration?
5. What is the pH range of human blood?
6. What is the unit of pH?
7. How will you calculate the amount of HCl?
8. How is glass electrode represented?
9. Why is glass electrode known as ion selective electrode?
10. What is the chemical reaction involved in this titration?





28




SHORT PROCEDURE


CONTENTS
TITRATION
Burette solution

Std Sodium Hydroxide

Pipette solution

20 ml mixture of acid (HCl+ CH 3COOH)


Additional solution

20 ml distilled water


End point

Conductivity decreases-slowly increases-Sudden increase



Equivalent Weight of HCl = 36.5


Equivalent Weight of CH 3COOH = 60



MODEL GRAPH


Conductance
Volume of NaOH
Mixture of Acids






29




Expt. No. 5 CONDUCTOMETRIC TITRATION OF MIXTURE
OF ACIDS

AIM
To determine the amount of a strong acid and a weak acid present in the given solution.

PRINCIPLE

Solution of electrolytes conducts electricity due to the presence of ions. Since specific conductance of a
solution is proportional to the concentration of ions in it, conductance of the solution is measured during the titration.

HCl + NaOH ? NaCl + H 2O (I neutralization)

CH 3COOH + NaOH ? CH 3COONa + H 2O (II neutralization)

When a solution of HCl is treated with NaOH the fast moving hydrogen ions are progressively replaced by
slow moving sodium ions. As a result conductance of the solution decreases. This decrease will take place until the
first neutralisation point is reached. Further addition of alkali results in formation of sodium acetate.

Since sodium acetate is stronger than acetic acid conductivity slowly increases until all acetic acid is
completely neutralized.(II Neutralisation) This is due to the presence of fast moving OH
-
ions. Anymore addition of
alkali increases the conductance sharply.

PROCEDURE
The burette is filled with NaOH solution upto zero mark. The given unknown solution (mixture of a weak &
a strong acid) is transferred into a 100ml standard flask and made upto the mark with distilled water. 20ml of the
made up solution is pipetted out into a clean 100ml beaker. The solution is diluted to 20ml using distilled water. A
conductivity cell is dipped into the solution and the terminals are connected to a conductivity meter.
30


TITRATION


CALCULATION OF STRENGTH OF HCl
Volume of NaOH (V 1) = --------------- ml (titre value)
Strength of NaOH (N 1) = ---------------- N
Volume of HCl (V 2) = ------------ ml
Strength of HCl (N 2) = -------------- N

N 2 = V 1 N 1 / V 2
Strength of HCl = ---------------- N
CALCULATION OF STRENGTH OF CH3COOH
Volume of NaOH (V 1) = ------------ ml (titre value)
Strength of NaOH (N 1) = ------------ N
Volume of CH 3COOH (V 2) = ------------ ml
Strength of CH 3COOH (N 2) = ------------ N
N 2 = V 1 N 1 / V 2

Strength of CH 3COOH = ------------ N



S.No

Volume of NaOH
(ml)

Conductance (mho)

14

15

16

17
18
19
20

21
22
23
24
25
26

S.No

Volume of NaOH
(ml)

Conductance (mho)

1
2
3
4
5
6
7
8
9
10
11
12
13
31

The burette solution is added to the unknown solution in the beaker in 0.5 ml increments, the solution is
stirred using a glass rod, and the observed conductance values are read from the meter. The conductance values
show decrease in the initial values, then gradually increases and finally shows a steep increase. The titration hence
shows two end-points (i.e) I neutralization (weak acid) & II neutralization (strong acid).
The accurate end-point is obtained by plotting a graph between observed conductance Vs volume of
NaOH added.

RESULT
The strength of acids present in the given unknown solution are:
a) Strong acid = ---------------- N
b) Weak acid = -----------------N



VIVA-VOCE

1. What is weak acid?
2. How many end points are obtained from the graph? Comment two end points.
3. Why is the conductance increase in the first end point?
4. What mixture of acids used in this titration?
5. Write the neutralization reaction between CH 3COOH and NaOH.
6. What is the solution present in the conductivity cell?
7. What are strong and weak electrolytes?
8. Give an example for strong acid and weak acid.
9. What is the strong electrolyte of weak electrolyte?
10. Give an example for strong base.









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?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





3


PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)
1. Fundamentals
To provide students with a solid foundation in Mathematics, Science and fundamentals of engineering,
enabling them to apply, to find solutions for engineering problems and use this knowledge to acquire higher
education
2. Core Competence
To train the students in chemistry practicals so that they apply their knowledge and training to compare,
and to analyze various engineering industrial problems to find solutions
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice this enables
them to find solutions for the real time problems in industry, and to design products
4. Professionalism
To inculcate professional and effective communication skills, leadership qualities and team spirit in the
students to make them multi-faceted personalities and develop their ability to relate engineering issues to
broader social context
5. Lifelong Learning/Ethics
To demonstrate and practice ethical and professional responsibilities in the industry and society in the
large, through commitment and lifelong learning needed for successful professional career






4


PROGRAMME OUTCOMES (POs)
To demonstrate and apply knowledge of Mathematics, Science and engineering fundamentals in the following
experiments.
1 .To estimate HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. To determine total, temporary & permanent hardness of water by EDTA method.
3. To determine DO content of water sample by Winkler?s method.
4. To determine chloride content of water sample by Argentometric method.
5. To estimate copper content of the given solution by Iodometry.
6. To determine strength of given hydrochloric acid using pH meter.
7. To determine strength of acids in a mixture of acids using conductivity meter.
8. To determine iron content of the given solution using potentiometer.
9. To estimate iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. To estimate sodium and potassium present in water using flame photometer.
11. To determine molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. To determine Pseudo first order kinetics ? ester hydrolysis.
13. To determine Corrosion experiment ? weight loss method.
14. To estimate CMC.
15. To estimate Phase change in a solid.
16. To determine strength of strong acid vs strong base using conductivity meter.











5

BS8161 - CHEMISTRY LABORATORY
SYLLABUS


? To make the student to acquire practical skills in the determination of water quality
parameters through volumetric and instrumental analysis.

? ???? ??? ???? ?? ???? ? ? ?To acquaint the students with the determination of molecular weight of a polymer by
viscometery.

LIST OF EXPERIMENTS:
1. Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. Determination of total, temporary & permanent hardness of water by EDTA method.
3. Determination of DO content of water sample by Winkler?s method.
4. Determination of chloride content of water sample by Argentometric method.
5. Estimation of copper content of the given solution by Iodometry.
6. Determination of strength of given hydrochloric acid using pH meter.
7. Determination of strength of acids in a mixture of acids using conductivity meter.
8. Estimation of iron content of the given solution using potentiometer.
9. Estimation of iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. Estimation of sodium and potassium present in water using flame photometer.
11. Determination of molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. Pseudo first order kinetics ? ester hydrolysis.
13. Corrosion experiment ? weight loss method.
14. Determination of CMC.
15. Phase change in a solid.
16. Conductometric titration of strong acid vs strong base.




? The students will be outfitted with hands-on knowledge in the quantitative chemical
analysis of water quality related parameters.
COURSE OBJECTIVES
COURSE OUTCOMES
6


INDEX [ SEMESTER ? I ]


S.No.



Date


Experiment

Date of
submission



Mark


Signature

1.

Estimation of HCl using Na 2CO 3 as
primary standard and Determination of
alkalinity in water sample.



2.


Determination of total, temporary &
permanent hardness of water by EDTA
method.



3.


Determination of chloride content of water
sample by argentometric method.



4.


Determination of strength of given
hydrochloric acid using pH meter.



5.


Determination of strength of acids in a
mixture of acids using conductivity meter.



6.


Estimation of iron content of the given
solution using potentiometer.



7.





Conductometric titration of strong acid Vs
strong base.



8.



Estimation of copper content of the given
solution by Iodometry


9.
Estimation of sodium and potassium
present in water using flame photometer




7




CONTENTS


S.No.


NAME OF EXPERIMENT

PAGE
No.
SEMESTER - I
1.
Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in
water sample.
09
2. Determination of total, temporary & permanent hardness of water by EDTA method. 15
3. Determination of chloride content of water sample by Argentometric method. 21
4. Determination of strength of given hydrochloric acid using pH meter. 25
5. Determination of strength of acids in a mixture of acids using conductivity meter. 29
6. Estimation of iron content of the given solution using potentiometer. 33
7. Conductometric titration of strong acid Vs strong base.

39


42

8


Estimation of copper content of the given solution by Iodometry 43
9 Estimation of sodium and potassium present in water using flame photometer 47






8



SHORT PROCEDURE:

CONTENTS
TITRATION
Estimation of alkalinity in water sample
(Std HCl Vs water sample)

Burette solution

Std. HCl


Pipette solution

Water sample


Indicator


(i) Phenolphthalein
(ii) Methyl orange


End point

(i) Disappearance of pink colour
(ii) Appearance of reddish orange colour






Relationship
between P &M
Nature of alkalinity
Amount of individual
alkalinities
OH
-
HCO 3
-


CO 3
2-

P = M

only OH
-

P or M

?
0.0

0.0


2P = M

only CO 3
2-


2P or M


0.0


0.0


?

P =0, M?0

only HCO 3
-



M



0.0



?

0.0


2P > M


OH
-
&CO 3
2-


OH
-
= 2P-M
CO 3
2-
= 2(M-P)


?

0.0

?

P < ? M




HCO 3
-
&CO 3
2-


HCO 3
-
= M-2P
CO 3
2-
= 2P

0.0 ? ?




9





Expt. No. 1 DETERMINATION OF ALKALINITY IN WATER
AIM
To determine the type and amounts of alkalinity in the given water sample. A standard solution of Na 2CO 3
of strength ____N is given.

PRINCIPLE
Alkalinity in water is due to the presence of soluble hydroxides, bicarbonates and carbonates.
Determination of various types and amounts of alkalinity is easily carried out by titration with standard HCl
employing the indicators phenolphthalein and methyl orange independently or in succession.

The following reactions occur when different types of alkalinity are neutralized with acid.

OH
?
+ H
+
? H 2O completed at pH 8.2-9.0 ----- (1)

CO 3
2 ?
+ H
+
? HCO 3
?
----- (2)

HCO 3
?
+ H
+
? (H 2CO 3) ? H 2O + CO 2, completed at pH 4.2-5.5 ----- (3)

Neutralisation (1) & (2) will be notified by phenolphthalein end-point while all the three will be

accounted by
methyl orange end-point. Bicarbonate in eqn. (3) may be due to the existence of soluble free bicarbonate salts and
bicarbonates resulting from half neutralization of soluble carbonates (eqn. (2))

Various steps to be followed

a) A known volume of water sample is titrated against std. HCl using first phenolphthalein indicator till
end-point (P) and the titration is continued without break using methyl orange indicator till the end-
point (M).



10


Titration

Estimation of Alkalinity in water sample

Standard HCl Vs Water sample Indicator: 1. Phenolphthalein
2. Methyl Orange


S.No.
Volume
of water
sample (ml)
Burette Reading
Concordant value

Initial Phenolphthalein End
Point (P)
Methyl Orange End
Point (M)

1

2






CALCULATION

Hydroxide ion alkalinity
Volume of HCl (2P-M) = ???????ml

Strength of HCl = ???????? N

Volume of water sample = ???????...ml

Strength of water sample = Volume of HCl (2P-M) x Strength of HCl
Volume of water sample

=

? Hydroxide ion alkalinity in terms of
CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ??????.mg/l







11




b) From the magnitudes of the P & M, the nature of alkalinity can be arrived as follows:

(i) P = M => Presence of only OH
-

(ii) 2P = M => Presence of only CO 3
2-

(iii) P =0, M=0 => Presence of only HCO 3
-
(iv) 2P > M => Presence of OH
-
& CO 3
2-
(v) 2P < M => Presence of HCO 3
-
& CO 3
2-

(Mixture of OH
-
& HCO3
-
is not listed since they do not exist together and are considered equivalent to CO 3
2-
).

PROCEDURE
TITRATION
ESTIMATION OF ALKALINITY IN WATER SAMPLE

Exactly 20 ml of water sample is pipetted out into a clean conical flask. Few drops of phenolphthalein
indicator are added and titrated against a standardized HCl taken in the burette. The end point is the
disappearance of pink colour, which is noted as P. Few drops of methyl orange indicator is added to the same
solution. The solution turns to yellow. The titration is continued further by adding same HCl without break till the
end point is reached. The end point is the colour change from yellow to reddish orange.

The experiment is repeated to get concordant values. From the magnitudes of P & M values, the type of
alkalinity present in the water sample is inferred and the individual amounts are calculated and reported.










12


Carbonate ion alkalinity

Volume of HCl 2 (M ? P) = ??? ????????ml

Strength of HCl = ??.?????..???...N

Volume of water sample =........................................ml

Strength of water sample = Volume of HCl 2 (M ? P) x Strength of HCl
Volume of water sample

= ???????????.. N




? Carbonate ion alkalinity
in terms of CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ???????????mg/l

















13





RESULT

1) The type of alkalinity present in the water sample = -------------------------ions.

2) The individual amounts of alkalinity present in the water sample:
Hydroxide ion alkalinity

= ----------------- ppm
Carbonate ion alkalinity = ------------------ ppm
Bicarbonate ion alkalinity = ----------------- ppm





VIVA-VOCE


1. What is meant by alkalinity?
2. What are the ions responsible for alkalinity?
3. Why OH
-
and HCO 3
?
ions cannot exist together in water?
4. What are the ions responsible for alkalinity when 2P > M?
5. What is the pH range for both in acidic and basic solutions?
6. What is the colour of phenolphthalein in an acid and in an alkaline solution?
7. What is the purpose of using two indicators in same titration?
8. What are the possible combinations of ions for alkalinity?
9. How is the amount of alkalinity expressed?
10. What are the types of indicator used in this experiment?







14

SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II TITRATION III
Standardisation of
EDTA
(EDTA Vs Std
Hard water)
Determination of
total hardness
(Std EDTA Vs Hard
water sample)
Determination of
permanent hardness
(Std EDTA Vs Boiled
Hard water sample)

Burette solution

EDTA solution

EDTA solution

EDTA solution

Pipette solution

20ml Std. hard water

20 ml hard water sample

20ml boiled hard water sample

Indicator

2 drops of EBT

2 drops of EBT

2 drops of EBT

Additional soln.


Ammoniacal Buffer
solution (5ml)

Ammoniacal Buffer solution
(5ml)

Ammoniacal Buffer solution
(5ml)
End point Wine - red to Steel blue Wine - red to steel blue Wine - red to Steel blue




STANDARDISATION OF EDTA
Titration - I
Std. HARD WATER Vs EDTA Indicator: EBT

S. No.
Volume of std hard
water (ml)
Burette Reading Volume of
EDTA
(V 1) (ml)
Concordant value

Initial

Final



Volume of std .hard water taken = 20 ml
Volume of EDTA consumed (V 1) = --------------- ml
1 ml of std.hard water = 1mg of CaCO 3
20 ml of std hard water = 20 mg of CaCO 3

V 1 ml of EDTA solution containing 20 mg of CaCO 3
1 ml of EDTA solution = 20 / V 1 mg of CaCO 3
= -----------------------mg of CaCO 3


15

Expt. No. 2 DETERMINATION OF TOTAL, TEMPORARY AND
PERMANENT HARDNESS OF WATER

AIM
To estimate the amount of total, temporary & permanent hardness in the given sample of water.

PRINCIPLE
The estimation is based on the complexometric titration.

(i) Total hardness of water is estimated by titrating against EDTA using EBT indicator.
EBT+M ?[EBT-M] (unstable complex)
(EBT-M) (Unstable complex) +EDTA ? [EDTA-M] (stable complex) +EBT
EBT indicator forms wine- red colored complex with metal ions present in water. On addition of EDTA
metal ions preferably forms complexes with EDTA and steel blue EBT indicator is set free. Therefore
change of colour from wine- red to steel blue denotes the end point.

(ii) Temporary hardness is removed by boiling the water.
Ca (HCO 3) 2 ? CaCO 3 +CO 2 ?+H 2O
Mg (HCO 3) 2 ? Mg(OH) 2 +2CO 2 ?
The precipitate is filtered and the remaining permanent hardness is estimated using EDTA.

PROCEDURE

TITRATION ? I
STANDARDISATION OF EDTA

Pipette out 20ml of standard hard water into a 250ml conical flask. Add 5ml of buffer solution and 3
drops of eriochrome black T indictor. Titrate the solution with EDTA from the burette until the colour
changes from wine- red to steel blue at the end point. Repeat the titration for concordant values. Let the
titre value be V 1ml.


16


Titration-II
SAMPLE HARD WATER Vs Std EDTA Indicator: EBT

S.No. Volume of sample
hard water (ml)
Burette Reading Volume of
EDTA
(V 2) (ml)
Concordant value

Initial

Final




CALCULATION

Calculation of total hardness


Volume of EDTA consumed (V 2) = ------------------------- ml
1ml of EDTA = 20 / V 1 mg of CaCO 3
V 2 ml of EDTA = 20 / V 1 x V 2 mg of CaCO 3

( i.e), If 20ml of sample hard water contains 20 x V 2 mg of CaCO 3 / V 1

Then 1000ml of water sample = 20 x V 2 x 1000 / V 1 x 20 mg of CaCO 3

= 1000 x V 2 / V 1 mg of CaCO3

Total hardness of given water sample = ---------------------ppm









17



DETERMINATION OF TOTAL HARDNESS

Pipette out 20ml of sample hard water into a clean conical flask. Add 5ml of buffer solution and 4 -5
drops of Eriochrome black -T indicator. Titrate the wine - red coloured solution with EDTA from the burette until
the colour steel blue appears at the end point. Repeat the titration for concordant values. Let the titre value be
V 2ml.



DETERMINATION OF PERMANENT HARDNESS

Take 100ml of hard water sample in a 500ml beaker and boil gently for about 1hour. Cool, filter it into a
100ml standard flask and make the volume up to the mark. Take 20ml of this solution and proceed it in the same
way as in titration (I). The volume of EDTA consumed corresponds to the permanent hardness of the water
sample. Let the titre value be V 3ml. Temporary hardness is calculated by subtracting permanent hardness from
total hardness.





















18




DETERMINATION OF PERMANENT HARDNESS
BOILED SAMPLE WATER Vs Std. EDTA Indicator: EBT


S.No.
Volume of boiled
hard water (ml)
Burette Reading (ml) Volume of
EDTA
(ml)

Concordant value

Initial Final



CALCULATION OF PERMANENT HARDNESS


Volume of EDTA consumed V 3 = ---------------------ml

1ml of EDTA = 20 / V 1 mg of CaCO 3

V 3ml of EDTA = 20 / V 1 x V 3 mg of CaCO 3

(i.e) 20 ml of boiled sample hard water = 20 / V 1 x V 3 mg of CaCO 3

Then 1000ml of boiled water sample = 20 / V 1 x V 3 / 20 * 1000mg of CaCO 3

= 1000 x V 3 / V 1 mg of CaCO 3

permanent hardness of boiled water sample = -----------------ppm

Temporary hardness of the given water sample = Total hardness ? Permanent hardness

= ------------------ppm

19







RESULT

(i) Total hardness of the given sample water = -------------- ppm.
(ii) Permanent hardness of the given sample water = --------------- ppm.
(iii) Temporary hardness of the given sample water = ----------------ppm.







VIVA-VOCE

1. Define ? Hard water
2. What is the structure of EDTA?
3. How will you calculate temporary hardness?
4. What is the role of the buffer in EDTA titration?
5. What is the permissible limit of hardness in drinking water?
6. Name the hardness producing ions present in water.
7. Name two salts which are responsible for temporary hardness.
8. Why is CaCO 3 taken as the standard?
9. Write the expansion of EDTA.
10. What is meant by EBT?











20





SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II
Standardisation of
AgNO 3
Estimation of Chloride
Burette solution

AgNO 3 solution

Std. AgNO 3 solution

Pipette solution

20ml std KCl solution

20 ml water sample

Indicator

1ml K 2CrO 4

1ml K 2CrO 4


End point

yellow to reddish brown

yellow to reddish brown

Titration I
Std. AgNO3 Vs KCl Indicator: Potassium Chromate













CALCULATION

Volume of KCl (V 1) = ------- ml

Strength of KCl (N 1) = ------- N

Volume of Silver Nitrate (V 2) = -------- ml

Strength of Siver Nitrate V 1N 1
N 2 =
V 1

= --------------------- N

S.No.
Volume of KCl
(ml)
Burette Reading (ml)
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

21




Expt.No. 3 ESTIMATION OF CHLORIDE CONTENT IN WATER
(ARGENTOMETRIC METHOD)
AIM
To estimate the amount of chloride present in given water sample by Argentometric method (Mohr?s
method). You are provided with standard solution of NaCl of strength --------N and a approximately N/10 solution of
Silver nitrate.

PRINCIPLE
The Chloride ion in the form of NaCl, KCl, CaCl 2, MgCl 2 etc., present in the water sample can be estimated
by Argentometric method or known as Mohr?s method. It is an example for precipitation titration. The reaction
between std. Sodium chloride and Silver nitrate is given below.
AgNO 3 + NaCl ? AgCl ? + NaNO 3
The completion of reaction can be observed by employing potassium chromate as the indicator. The end
point is the colour change from yellow to reddish brown due to the following reaction.
2AgNO 3 + K 2CrO 4 ? Ag 2CrO 4 ? + 2KNO 3
Potassium chromate indicator will not be precipitated as silver chromate until all the chlorides in the solution
have been precipitated as AgCl Since a precipitation reaction takes place in preference, this reaction takes place
only at the end point.

PROCEDURE
TITRATION I: STANDARDISATION OF SILVER NITRATE
Pipette out 20ml of standard sodium or potassium chloride solution into a clean conical flask. Add 1ml of 5%
K 2CrO 4 indicator, as the solution turns yellow in colour. Titrate it against silver nitrate solution taken in the burette.
Observe the nearness of the end point through the formation of coagulated silver chloride precipitate at the bottom
of the flask. Now add the silver nitrate drop by drop until the solution gets a faint reddish brown tinge. Repeat the
titration for concordant value. Let the volume of silver nitrate be V 2ml.





22






TITRATION - II

Std AgNO3 Vs WATER SAMPLE Indicator: Potassium Chromate













CALCULATION

Volume of Silver Nitrate (V 3) = ------------ ml

Strength of Siver Nitrate (N 3) = ------------- N

Volume of Water sample (V 4) = -------------- ml

Strength of Water sample V 3 N 3
(N 4) =
V 4

= ----------------- N

Amount of Chloride ion present in 1000 ml of the water sample = Equivalent mass of HCl X 1000


= N 4 x 35.46 x 1000


= -----------------mg/l







S.No.
Volume of water
sample (ml)
Burette Reading
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

23





TITRATION - II
ESTIMATION OF CHLORIDE ION

Pipette out 40 ml of the given water sample into a clean conical flask.To this sample add 1ml of 5% K 2CrO 4
indicator and titrate it against the standardized silver nitrate solution taken in the burette and continue the titration
until the solution produces a reddish brown colour. Note down the end point and repeat the titration for
concordance. Let the volume be V 3ml.







RESULT

The amount of chloride ion present in the water sample = ----------------- mg/l.




VIVA-VOCE

1. Why is this method known as Argentometric method?
2.
What is the chemical reaction between AgNO 3 and Cl
-
ions present in water?

3.
What is the form of Chloride ion present in water?

4. What is the reaction between AgNO 3 and K 2CrO 4 ?
5. What is the name of the method used in this titration?
6. Name the link solution used in the determination.
7. Name the solution used to standardize AgNO 3.
8. What is the indicator used in the determination?
9. How will you calculate the amount of chloride ion in the given solution?
10. What is the colour change in the titration?




24




SHORT PROCEDURE


CONTENTS

TITRATION I

TITRATION II
Burette solution

Std Sodium Hydroxide

Std Sodium Hydroxide

Pipette solution

20 ml hydrochloric acid 20 ml hydrochloric acid
Additional solution


20 ml distilled water

20 ml distilled water


End point



Sudden increase in pH
pH gradual increase

Equivalent Weight of HCl = 36.5







ROUGH GRAPH FAIR GRAPH











pH
? pH/ ? V





Volume of NaOH
(ml)
Volume of NaOH
(ml)





25



Expt. No. 4 DETERMINATION OF STRENGTH OF HCl by pH METRY

AIM
To determine the strength of given HCl by pH metry. A standard solution of 0.1N NaOH is provided.

PRINCIPLE
The pH of a solution is related to H
+
ion concentration by the following formula.

. pH = -log [ H
+
]

pH of a solution is indirectly related to H
+
ion concentration. When NaOH is added slowly to HCl, H
+
ions
get neutralized by OH
-
ions. The pH increases slowly.

H
+
+ Cl
-
+ Na
+
+ OH
-
? Na
+
+ Cl
-
+H 2O

When all H
+
ions of HCl are neutralized at the end point, addition of NaOH causes high increase in pH
because of the addition of excess OH
-
ions.

MATERIALS REQUIRED
pH meter, Glass electrode, Burette, Pipette, Std.NaOH, approximately N/10 HCl .

PROCEDURE

The burette is washed with distilled water, rinsed with the given std. Sodium hydroxide and filled with the
same solution. Exactly 10ml of the given HCl solution is pipetted out into a clean beaker. It is then diluted to 50ml
with distilled water. A glass electrode is dipped into the solution and its terminals are connected to a pH meter.

26

TITRATION - I
S.No Volume of
NaOH (ml)
pH
1

2

3

4

5

6

7

8

9

10


TITRATION - II



CALCULATION

Volume of NaOH (V 1) = ------------------- ml ( titre value)
Strength of NaOH (N 1) = ------------------- N
Volume of HCl (V 2) = ------------------ml
Strength of HCl (N 2) = ------------------ N
N 2 = V 1 N 1 / V 2
Strength of HCl = -------------------- N
Amount of HCl present in 1000ml of the given solution = Strength x equivalent weight of HCl
= ------------------ X 36.5
= --------------------- g
S.No Volume of
NaOH (ml)
pH
11

12

13

14

15

16

17

18

19

20

S.No
Volume of
NaOH (ml)
pH ?pH ?V ?pH / ?V
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
27



Now NaOH is gradually added from the burette to HCl taken in the beaker. pH of the solution is noted for
each addition of NaOH. This process is continued until 5 readings are taken after the end point.
A fair titration is performed to find the exact end point.





RESULT

(i) Strength of the given HCl solution = ---------------- N
(ii) Amount of HCl present in a litre of the solution = ---------------- g


VIVA-VOCE

1. What is meant by pH?
2. What is the name of the reference electrode used ?
3. Why does pH value increase suddenly at the end point?
4. What is the indicator used in the titration?
5. What is the pH range of human blood?
6. What is the unit of pH?
7. How will you calculate the amount of HCl?
8. How is glass electrode represented?
9. Why is glass electrode known as ion selective electrode?
10. What is the chemical reaction involved in this titration?





28




SHORT PROCEDURE


CONTENTS
TITRATION
Burette solution

Std Sodium Hydroxide

Pipette solution

20 ml mixture of acid (HCl+ CH 3COOH)


Additional solution

20 ml distilled water


End point

Conductivity decreases-slowly increases-Sudden increase



Equivalent Weight of HCl = 36.5


Equivalent Weight of CH 3COOH = 60



MODEL GRAPH


Conductance
Volume of NaOH
Mixture of Acids






29




Expt. No. 5 CONDUCTOMETRIC TITRATION OF MIXTURE
OF ACIDS

AIM
To determine the amount of a strong acid and a weak acid present in the given solution.

PRINCIPLE

Solution of electrolytes conducts electricity due to the presence of ions. Since specific conductance of a
solution is proportional to the concentration of ions in it, conductance of the solution is measured during the titration.

HCl + NaOH ? NaCl + H 2O (I neutralization)

CH 3COOH + NaOH ? CH 3COONa + H 2O (II neutralization)

When a solution of HCl is treated with NaOH the fast moving hydrogen ions are progressively replaced by
slow moving sodium ions. As a result conductance of the solution decreases. This decrease will take place until the
first neutralisation point is reached. Further addition of alkali results in formation of sodium acetate.

Since sodium acetate is stronger than acetic acid conductivity slowly increases until all acetic acid is
completely neutralized.(II Neutralisation) This is due to the presence of fast moving OH
-
ions. Anymore addition of
alkali increases the conductance sharply.

PROCEDURE
The burette is filled with NaOH solution upto zero mark. The given unknown solution (mixture of a weak &
a strong acid) is transferred into a 100ml standard flask and made upto the mark with distilled water. 20ml of the
made up solution is pipetted out into a clean 100ml beaker. The solution is diluted to 20ml using distilled water. A
conductivity cell is dipped into the solution and the terminals are connected to a conductivity meter.
30


TITRATION


CALCULATION OF STRENGTH OF HCl
Volume of NaOH (V 1) = --------------- ml (titre value)
Strength of NaOH (N 1) = ---------------- N
Volume of HCl (V 2) = ------------ ml
Strength of HCl (N 2) = -------------- N

N 2 = V 1 N 1 / V 2
Strength of HCl = ---------------- N
CALCULATION OF STRENGTH OF CH3COOH
Volume of NaOH (V 1) = ------------ ml (titre value)
Strength of NaOH (N 1) = ------------ N
Volume of CH 3COOH (V 2) = ------------ ml
Strength of CH 3COOH (N 2) = ------------ N
N 2 = V 1 N 1 / V 2

Strength of CH 3COOH = ------------ N



S.No

Volume of NaOH
(ml)

Conductance (mho)

14

15

16

17
18
19
20

21
22
23
24
25
26

S.No

Volume of NaOH
(ml)

Conductance (mho)

1
2
3
4
5
6
7
8
9
10
11
12
13
31

The burette solution is added to the unknown solution in the beaker in 0.5 ml increments, the solution is
stirred using a glass rod, and the observed conductance values are read from the meter. The conductance values
show decrease in the initial values, then gradually increases and finally shows a steep increase. The titration hence
shows two end-points (i.e) I neutralization (weak acid) & II neutralization (strong acid).
The accurate end-point is obtained by plotting a graph between observed conductance Vs volume of
NaOH added.

RESULT
The strength of acids present in the given unknown solution are:
a) Strong acid = ---------------- N
b) Weak acid = -----------------N



VIVA-VOCE

1. What is weak acid?
2. How many end points are obtained from the graph? Comment two end points.
3. Why is the conductance increase in the first end point?
4. What mixture of acids used in this titration?
5. Write the neutralization reaction between CH 3COOH and NaOH.
6. What is the solution present in the conductivity cell?
7. What are strong and weak electrolytes?
8. Give an example for strong acid and weak acid.
9. What is the strong electrolyte of weak electrolyte?
10. Give an example for strong base.









32

SHORT PROCEDURE



















ROUGH GRAPH







EMF(mV)






Volume of Potassium dichromate (ml)

FAIR GRAPH









? E / ? V

Volume of Potassium dichromate (ml)




CONTENTS

TITRATION I

TITRATION II
Burette solution

Std Potassium dichromate

Std Potassium dichromate

Pipette solution

10 ml of FAS


10 ml of FAS



Additional
solution

20 ml distilled water+
10 ml of dil H 2SO 4


20 ml distilled water+
10 ml of dil H 2SO 4

End point

Sudden increase in EMF

EMF increases and decreases

Equivalent Weight of Ferrous ion = 55.85

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?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





3


PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)
1. Fundamentals
To provide students with a solid foundation in Mathematics, Science and fundamentals of engineering,
enabling them to apply, to find solutions for engineering problems and use this knowledge to acquire higher
education
2. Core Competence
To train the students in chemistry practicals so that they apply their knowledge and training to compare,
and to analyze various engineering industrial problems to find solutions
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice this enables
them to find solutions for the real time problems in industry, and to design products
4. Professionalism
To inculcate professional and effective communication skills, leadership qualities and team spirit in the
students to make them multi-faceted personalities and develop their ability to relate engineering issues to
broader social context
5. Lifelong Learning/Ethics
To demonstrate and practice ethical and professional responsibilities in the industry and society in the
large, through commitment and lifelong learning needed for successful professional career






4


PROGRAMME OUTCOMES (POs)
To demonstrate and apply knowledge of Mathematics, Science and engineering fundamentals in the following
experiments.
1 .To estimate HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. To determine total, temporary & permanent hardness of water by EDTA method.
3. To determine DO content of water sample by Winkler?s method.
4. To determine chloride content of water sample by Argentometric method.
5. To estimate copper content of the given solution by Iodometry.
6. To determine strength of given hydrochloric acid using pH meter.
7. To determine strength of acids in a mixture of acids using conductivity meter.
8. To determine iron content of the given solution using potentiometer.
9. To estimate iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. To estimate sodium and potassium present in water using flame photometer.
11. To determine molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. To determine Pseudo first order kinetics ? ester hydrolysis.
13. To determine Corrosion experiment ? weight loss method.
14. To estimate CMC.
15. To estimate Phase change in a solid.
16. To determine strength of strong acid vs strong base using conductivity meter.











5

BS8161 - CHEMISTRY LABORATORY
SYLLABUS


? To make the student to acquire practical skills in the determination of water quality
parameters through volumetric and instrumental analysis.

? ???? ??? ???? ?? ???? ? ? ?To acquaint the students with the determination of molecular weight of a polymer by
viscometery.

LIST OF EXPERIMENTS:
1. Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. Determination of total, temporary & permanent hardness of water by EDTA method.
3. Determination of DO content of water sample by Winkler?s method.
4. Determination of chloride content of water sample by Argentometric method.
5. Estimation of copper content of the given solution by Iodometry.
6. Determination of strength of given hydrochloric acid using pH meter.
7. Determination of strength of acids in a mixture of acids using conductivity meter.
8. Estimation of iron content of the given solution using potentiometer.
9. Estimation of iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. Estimation of sodium and potassium present in water using flame photometer.
11. Determination of molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. Pseudo first order kinetics ? ester hydrolysis.
13. Corrosion experiment ? weight loss method.
14. Determination of CMC.
15. Phase change in a solid.
16. Conductometric titration of strong acid vs strong base.




? The students will be outfitted with hands-on knowledge in the quantitative chemical
analysis of water quality related parameters.
COURSE OBJECTIVES
COURSE OUTCOMES
6


INDEX [ SEMESTER ? I ]


S.No.



Date


Experiment

Date of
submission



Mark


Signature

1.

Estimation of HCl using Na 2CO 3 as
primary standard and Determination of
alkalinity in water sample.



2.


Determination of total, temporary &
permanent hardness of water by EDTA
method.



3.


Determination of chloride content of water
sample by argentometric method.



4.


Determination of strength of given
hydrochloric acid using pH meter.



5.


Determination of strength of acids in a
mixture of acids using conductivity meter.



6.


Estimation of iron content of the given
solution using potentiometer.



7.





Conductometric titration of strong acid Vs
strong base.



8.



Estimation of copper content of the given
solution by Iodometry


9.
Estimation of sodium and potassium
present in water using flame photometer




7




CONTENTS


S.No.


NAME OF EXPERIMENT

PAGE
No.
SEMESTER - I
1.
Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in
water sample.
09
2. Determination of total, temporary & permanent hardness of water by EDTA method. 15
3. Determination of chloride content of water sample by Argentometric method. 21
4. Determination of strength of given hydrochloric acid using pH meter. 25
5. Determination of strength of acids in a mixture of acids using conductivity meter. 29
6. Estimation of iron content of the given solution using potentiometer. 33
7. Conductometric titration of strong acid Vs strong base.

39


42

8


Estimation of copper content of the given solution by Iodometry 43
9 Estimation of sodium and potassium present in water using flame photometer 47






8



SHORT PROCEDURE:

CONTENTS
TITRATION
Estimation of alkalinity in water sample
(Std HCl Vs water sample)

Burette solution

Std. HCl


Pipette solution

Water sample


Indicator


(i) Phenolphthalein
(ii) Methyl orange


End point

(i) Disappearance of pink colour
(ii) Appearance of reddish orange colour






Relationship
between P &M
Nature of alkalinity
Amount of individual
alkalinities
OH
-
HCO 3
-


CO 3
2-

P = M

only OH
-

P or M

?
0.0

0.0


2P = M

only CO 3
2-


2P or M


0.0


0.0


?

P =0, M?0

only HCO 3
-



M



0.0



?

0.0


2P > M


OH
-
&CO 3
2-


OH
-
= 2P-M
CO 3
2-
= 2(M-P)


?

0.0

?

P < ? M




HCO 3
-
&CO 3
2-


HCO 3
-
= M-2P
CO 3
2-
= 2P

0.0 ? ?




9





Expt. No. 1 DETERMINATION OF ALKALINITY IN WATER
AIM
To determine the type and amounts of alkalinity in the given water sample. A standard solution of Na 2CO 3
of strength ____N is given.

PRINCIPLE
Alkalinity in water is due to the presence of soluble hydroxides, bicarbonates and carbonates.
Determination of various types and amounts of alkalinity is easily carried out by titration with standard HCl
employing the indicators phenolphthalein and methyl orange independently or in succession.

The following reactions occur when different types of alkalinity are neutralized with acid.

OH
?
+ H
+
? H 2O completed at pH 8.2-9.0 ----- (1)

CO 3
2 ?
+ H
+
? HCO 3
?
----- (2)

HCO 3
?
+ H
+
? (H 2CO 3) ? H 2O + CO 2, completed at pH 4.2-5.5 ----- (3)

Neutralisation (1) & (2) will be notified by phenolphthalein end-point while all the three will be

accounted by
methyl orange end-point. Bicarbonate in eqn. (3) may be due to the existence of soluble free bicarbonate salts and
bicarbonates resulting from half neutralization of soluble carbonates (eqn. (2))

Various steps to be followed

a) A known volume of water sample is titrated against std. HCl using first phenolphthalein indicator till
end-point (P) and the titration is continued without break using methyl orange indicator till the end-
point (M).



10


Titration

Estimation of Alkalinity in water sample

Standard HCl Vs Water sample Indicator: 1. Phenolphthalein
2. Methyl Orange


S.No.
Volume
of water
sample (ml)
Burette Reading
Concordant value

Initial Phenolphthalein End
Point (P)
Methyl Orange End
Point (M)

1

2






CALCULATION

Hydroxide ion alkalinity
Volume of HCl (2P-M) = ???????ml

Strength of HCl = ???????? N

Volume of water sample = ???????...ml

Strength of water sample = Volume of HCl (2P-M) x Strength of HCl
Volume of water sample

=

? Hydroxide ion alkalinity in terms of
CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ??????.mg/l







11




b) From the magnitudes of the P & M, the nature of alkalinity can be arrived as follows:

(i) P = M => Presence of only OH
-

(ii) 2P = M => Presence of only CO 3
2-

(iii) P =0, M=0 => Presence of only HCO 3
-
(iv) 2P > M => Presence of OH
-
& CO 3
2-
(v) 2P < M => Presence of HCO 3
-
& CO 3
2-

(Mixture of OH
-
& HCO3
-
is not listed since they do not exist together and are considered equivalent to CO 3
2-
).

PROCEDURE
TITRATION
ESTIMATION OF ALKALINITY IN WATER SAMPLE

Exactly 20 ml of water sample is pipetted out into a clean conical flask. Few drops of phenolphthalein
indicator are added and titrated against a standardized HCl taken in the burette. The end point is the
disappearance of pink colour, which is noted as P. Few drops of methyl orange indicator is added to the same
solution. The solution turns to yellow. The titration is continued further by adding same HCl without break till the
end point is reached. The end point is the colour change from yellow to reddish orange.

The experiment is repeated to get concordant values. From the magnitudes of P & M values, the type of
alkalinity present in the water sample is inferred and the individual amounts are calculated and reported.










12


Carbonate ion alkalinity

Volume of HCl 2 (M ? P) = ??? ????????ml

Strength of HCl = ??.?????..???...N

Volume of water sample =........................................ml

Strength of water sample = Volume of HCl 2 (M ? P) x Strength of HCl
Volume of water sample

= ???????????.. N




? Carbonate ion alkalinity
in terms of CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ???????????mg/l

















13





RESULT

1) The type of alkalinity present in the water sample = -------------------------ions.

2) The individual amounts of alkalinity present in the water sample:
Hydroxide ion alkalinity

= ----------------- ppm
Carbonate ion alkalinity = ------------------ ppm
Bicarbonate ion alkalinity = ----------------- ppm





VIVA-VOCE


1. What is meant by alkalinity?
2. What are the ions responsible for alkalinity?
3. Why OH
-
and HCO 3
?
ions cannot exist together in water?
4. What are the ions responsible for alkalinity when 2P > M?
5. What is the pH range for both in acidic and basic solutions?
6. What is the colour of phenolphthalein in an acid and in an alkaline solution?
7. What is the purpose of using two indicators in same titration?
8. What are the possible combinations of ions for alkalinity?
9. How is the amount of alkalinity expressed?
10. What are the types of indicator used in this experiment?







14

SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II TITRATION III
Standardisation of
EDTA
(EDTA Vs Std
Hard water)
Determination of
total hardness
(Std EDTA Vs Hard
water sample)
Determination of
permanent hardness
(Std EDTA Vs Boiled
Hard water sample)

Burette solution

EDTA solution

EDTA solution

EDTA solution

Pipette solution

20ml Std. hard water

20 ml hard water sample

20ml boiled hard water sample

Indicator

2 drops of EBT

2 drops of EBT

2 drops of EBT

Additional soln.


Ammoniacal Buffer
solution (5ml)

Ammoniacal Buffer solution
(5ml)

Ammoniacal Buffer solution
(5ml)
End point Wine - red to Steel blue Wine - red to steel blue Wine - red to Steel blue




STANDARDISATION OF EDTA
Titration - I
Std. HARD WATER Vs EDTA Indicator: EBT

S. No.
Volume of std hard
water (ml)
Burette Reading Volume of
EDTA
(V 1) (ml)
Concordant value

Initial

Final



Volume of std .hard water taken = 20 ml
Volume of EDTA consumed (V 1) = --------------- ml
1 ml of std.hard water = 1mg of CaCO 3
20 ml of std hard water = 20 mg of CaCO 3

V 1 ml of EDTA solution containing 20 mg of CaCO 3
1 ml of EDTA solution = 20 / V 1 mg of CaCO 3
= -----------------------mg of CaCO 3


15

Expt. No. 2 DETERMINATION OF TOTAL, TEMPORARY AND
PERMANENT HARDNESS OF WATER

AIM
To estimate the amount of total, temporary & permanent hardness in the given sample of water.

PRINCIPLE
The estimation is based on the complexometric titration.

(i) Total hardness of water is estimated by titrating against EDTA using EBT indicator.
EBT+M ?[EBT-M] (unstable complex)
(EBT-M) (Unstable complex) +EDTA ? [EDTA-M] (stable complex) +EBT
EBT indicator forms wine- red colored complex with metal ions present in water. On addition of EDTA
metal ions preferably forms complexes with EDTA and steel blue EBT indicator is set free. Therefore
change of colour from wine- red to steel blue denotes the end point.

(ii) Temporary hardness is removed by boiling the water.
Ca (HCO 3) 2 ? CaCO 3 +CO 2 ?+H 2O
Mg (HCO 3) 2 ? Mg(OH) 2 +2CO 2 ?
The precipitate is filtered and the remaining permanent hardness is estimated using EDTA.

PROCEDURE

TITRATION ? I
STANDARDISATION OF EDTA

Pipette out 20ml of standard hard water into a 250ml conical flask. Add 5ml of buffer solution and 3
drops of eriochrome black T indictor. Titrate the solution with EDTA from the burette until the colour
changes from wine- red to steel blue at the end point. Repeat the titration for concordant values. Let the
titre value be V 1ml.


16


Titration-II
SAMPLE HARD WATER Vs Std EDTA Indicator: EBT

S.No. Volume of sample
hard water (ml)
Burette Reading Volume of
EDTA
(V 2) (ml)
Concordant value

Initial

Final




CALCULATION

Calculation of total hardness


Volume of EDTA consumed (V 2) = ------------------------- ml
1ml of EDTA = 20 / V 1 mg of CaCO 3
V 2 ml of EDTA = 20 / V 1 x V 2 mg of CaCO 3

( i.e), If 20ml of sample hard water contains 20 x V 2 mg of CaCO 3 / V 1

Then 1000ml of water sample = 20 x V 2 x 1000 / V 1 x 20 mg of CaCO 3

= 1000 x V 2 / V 1 mg of CaCO3

Total hardness of given water sample = ---------------------ppm









17



DETERMINATION OF TOTAL HARDNESS

Pipette out 20ml of sample hard water into a clean conical flask. Add 5ml of buffer solution and 4 -5
drops of Eriochrome black -T indicator. Titrate the wine - red coloured solution with EDTA from the burette until
the colour steel blue appears at the end point. Repeat the titration for concordant values. Let the titre value be
V 2ml.



DETERMINATION OF PERMANENT HARDNESS

Take 100ml of hard water sample in a 500ml beaker and boil gently for about 1hour. Cool, filter it into a
100ml standard flask and make the volume up to the mark. Take 20ml of this solution and proceed it in the same
way as in titration (I). The volume of EDTA consumed corresponds to the permanent hardness of the water
sample. Let the titre value be V 3ml. Temporary hardness is calculated by subtracting permanent hardness from
total hardness.





















18




DETERMINATION OF PERMANENT HARDNESS
BOILED SAMPLE WATER Vs Std. EDTA Indicator: EBT


S.No.
Volume of boiled
hard water (ml)
Burette Reading (ml) Volume of
EDTA
(ml)

Concordant value

Initial Final



CALCULATION OF PERMANENT HARDNESS


Volume of EDTA consumed V 3 = ---------------------ml

1ml of EDTA = 20 / V 1 mg of CaCO 3

V 3ml of EDTA = 20 / V 1 x V 3 mg of CaCO 3

(i.e) 20 ml of boiled sample hard water = 20 / V 1 x V 3 mg of CaCO 3

Then 1000ml of boiled water sample = 20 / V 1 x V 3 / 20 * 1000mg of CaCO 3

= 1000 x V 3 / V 1 mg of CaCO 3

permanent hardness of boiled water sample = -----------------ppm

Temporary hardness of the given water sample = Total hardness ? Permanent hardness

= ------------------ppm

19







RESULT

(i) Total hardness of the given sample water = -------------- ppm.
(ii) Permanent hardness of the given sample water = --------------- ppm.
(iii) Temporary hardness of the given sample water = ----------------ppm.







VIVA-VOCE

1. Define ? Hard water
2. What is the structure of EDTA?
3. How will you calculate temporary hardness?
4. What is the role of the buffer in EDTA titration?
5. What is the permissible limit of hardness in drinking water?
6. Name the hardness producing ions present in water.
7. Name two salts which are responsible for temporary hardness.
8. Why is CaCO 3 taken as the standard?
9. Write the expansion of EDTA.
10. What is meant by EBT?











20





SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II
Standardisation of
AgNO 3
Estimation of Chloride
Burette solution

AgNO 3 solution

Std. AgNO 3 solution

Pipette solution

20ml std KCl solution

20 ml water sample

Indicator

1ml K 2CrO 4

1ml K 2CrO 4


End point

yellow to reddish brown

yellow to reddish brown

Titration I
Std. AgNO3 Vs KCl Indicator: Potassium Chromate













CALCULATION

Volume of KCl (V 1) = ------- ml

Strength of KCl (N 1) = ------- N

Volume of Silver Nitrate (V 2) = -------- ml

Strength of Siver Nitrate V 1N 1
N 2 =
V 1

= --------------------- N

S.No.
Volume of KCl
(ml)
Burette Reading (ml)
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

21




Expt.No. 3 ESTIMATION OF CHLORIDE CONTENT IN WATER
(ARGENTOMETRIC METHOD)
AIM
To estimate the amount of chloride present in given water sample by Argentometric method (Mohr?s
method). You are provided with standard solution of NaCl of strength --------N and a approximately N/10 solution of
Silver nitrate.

PRINCIPLE
The Chloride ion in the form of NaCl, KCl, CaCl 2, MgCl 2 etc., present in the water sample can be estimated
by Argentometric method or known as Mohr?s method. It is an example for precipitation titration. The reaction
between std. Sodium chloride and Silver nitrate is given below.
AgNO 3 + NaCl ? AgCl ? + NaNO 3
The completion of reaction can be observed by employing potassium chromate as the indicator. The end
point is the colour change from yellow to reddish brown due to the following reaction.
2AgNO 3 + K 2CrO 4 ? Ag 2CrO 4 ? + 2KNO 3
Potassium chromate indicator will not be precipitated as silver chromate until all the chlorides in the solution
have been precipitated as AgCl Since a precipitation reaction takes place in preference, this reaction takes place
only at the end point.

PROCEDURE
TITRATION I: STANDARDISATION OF SILVER NITRATE
Pipette out 20ml of standard sodium or potassium chloride solution into a clean conical flask. Add 1ml of 5%
K 2CrO 4 indicator, as the solution turns yellow in colour. Titrate it against silver nitrate solution taken in the burette.
Observe the nearness of the end point through the formation of coagulated silver chloride precipitate at the bottom
of the flask. Now add the silver nitrate drop by drop until the solution gets a faint reddish brown tinge. Repeat the
titration for concordant value. Let the volume of silver nitrate be V 2ml.





22






TITRATION - II

Std AgNO3 Vs WATER SAMPLE Indicator: Potassium Chromate













CALCULATION

Volume of Silver Nitrate (V 3) = ------------ ml

Strength of Siver Nitrate (N 3) = ------------- N

Volume of Water sample (V 4) = -------------- ml

Strength of Water sample V 3 N 3
(N 4) =
V 4

= ----------------- N

Amount of Chloride ion present in 1000 ml of the water sample = Equivalent mass of HCl X 1000


= N 4 x 35.46 x 1000


= -----------------mg/l







S.No.
Volume of water
sample (ml)
Burette Reading
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

23





TITRATION - II
ESTIMATION OF CHLORIDE ION

Pipette out 40 ml of the given water sample into a clean conical flask.To this sample add 1ml of 5% K 2CrO 4
indicator and titrate it against the standardized silver nitrate solution taken in the burette and continue the titration
until the solution produces a reddish brown colour. Note down the end point and repeat the titration for
concordance. Let the volume be V 3ml.







RESULT

The amount of chloride ion present in the water sample = ----------------- mg/l.




VIVA-VOCE

1. Why is this method known as Argentometric method?
2.
What is the chemical reaction between AgNO 3 and Cl
-
ions present in water?

3.
What is the form of Chloride ion present in water?

4. What is the reaction between AgNO 3 and K 2CrO 4 ?
5. What is the name of the method used in this titration?
6. Name the link solution used in the determination.
7. Name the solution used to standardize AgNO 3.
8. What is the indicator used in the determination?
9. How will you calculate the amount of chloride ion in the given solution?
10. What is the colour change in the titration?




24




SHORT PROCEDURE


CONTENTS

TITRATION I

TITRATION II
Burette solution

Std Sodium Hydroxide

Std Sodium Hydroxide

Pipette solution

20 ml hydrochloric acid 20 ml hydrochloric acid
Additional solution


20 ml distilled water

20 ml distilled water


End point



Sudden increase in pH
pH gradual increase

Equivalent Weight of HCl = 36.5







ROUGH GRAPH FAIR GRAPH











pH
? pH/ ? V





Volume of NaOH
(ml)
Volume of NaOH
(ml)





25



Expt. No. 4 DETERMINATION OF STRENGTH OF HCl by pH METRY

AIM
To determine the strength of given HCl by pH metry. A standard solution of 0.1N NaOH is provided.

PRINCIPLE
The pH of a solution is related to H
+
ion concentration by the following formula.

. pH = -log [ H
+
]

pH of a solution is indirectly related to H
+
ion concentration. When NaOH is added slowly to HCl, H
+
ions
get neutralized by OH
-
ions. The pH increases slowly.

H
+
+ Cl
-
+ Na
+
+ OH
-
? Na
+
+ Cl
-
+H 2O

When all H
+
ions of HCl are neutralized at the end point, addition of NaOH causes high increase in pH
because of the addition of excess OH
-
ions.

MATERIALS REQUIRED
pH meter, Glass electrode, Burette, Pipette, Std.NaOH, approximately N/10 HCl .

PROCEDURE

The burette is washed with distilled water, rinsed with the given std. Sodium hydroxide and filled with the
same solution. Exactly 10ml of the given HCl solution is pipetted out into a clean beaker. It is then diluted to 50ml
with distilled water. A glass electrode is dipped into the solution and its terminals are connected to a pH meter.

26

TITRATION - I
S.No Volume of
NaOH (ml)
pH
1

2

3

4

5

6

7

8

9

10


TITRATION - II



CALCULATION

Volume of NaOH (V 1) = ------------------- ml ( titre value)
Strength of NaOH (N 1) = ------------------- N
Volume of HCl (V 2) = ------------------ml
Strength of HCl (N 2) = ------------------ N
N 2 = V 1 N 1 / V 2
Strength of HCl = -------------------- N
Amount of HCl present in 1000ml of the given solution = Strength x equivalent weight of HCl
= ------------------ X 36.5
= --------------------- g
S.No Volume of
NaOH (ml)
pH
11

12

13

14

15

16

17

18

19

20

S.No
Volume of
NaOH (ml)
pH ?pH ?V ?pH / ?V
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
27



Now NaOH is gradually added from the burette to HCl taken in the beaker. pH of the solution is noted for
each addition of NaOH. This process is continued until 5 readings are taken after the end point.
A fair titration is performed to find the exact end point.





RESULT

(i) Strength of the given HCl solution = ---------------- N
(ii) Amount of HCl present in a litre of the solution = ---------------- g


VIVA-VOCE

1. What is meant by pH?
2. What is the name of the reference electrode used ?
3. Why does pH value increase suddenly at the end point?
4. What is the indicator used in the titration?
5. What is the pH range of human blood?
6. What is the unit of pH?
7. How will you calculate the amount of HCl?
8. How is glass electrode represented?
9. Why is glass electrode known as ion selective electrode?
10. What is the chemical reaction involved in this titration?





28




SHORT PROCEDURE


CONTENTS
TITRATION
Burette solution

Std Sodium Hydroxide

Pipette solution

20 ml mixture of acid (HCl+ CH 3COOH)


Additional solution

20 ml distilled water


End point

Conductivity decreases-slowly increases-Sudden increase



Equivalent Weight of HCl = 36.5


Equivalent Weight of CH 3COOH = 60



MODEL GRAPH


Conductance
Volume of NaOH
Mixture of Acids






29




Expt. No. 5 CONDUCTOMETRIC TITRATION OF MIXTURE
OF ACIDS

AIM
To determine the amount of a strong acid and a weak acid present in the given solution.

PRINCIPLE

Solution of electrolytes conducts electricity due to the presence of ions. Since specific conductance of a
solution is proportional to the concentration of ions in it, conductance of the solution is measured during the titration.

HCl + NaOH ? NaCl + H 2O (I neutralization)

CH 3COOH + NaOH ? CH 3COONa + H 2O (II neutralization)

When a solution of HCl is treated with NaOH the fast moving hydrogen ions are progressively replaced by
slow moving sodium ions. As a result conductance of the solution decreases. This decrease will take place until the
first neutralisation point is reached. Further addition of alkali results in formation of sodium acetate.

Since sodium acetate is stronger than acetic acid conductivity slowly increases until all acetic acid is
completely neutralized.(II Neutralisation) This is due to the presence of fast moving OH
-
ions. Anymore addition of
alkali increases the conductance sharply.

PROCEDURE
The burette is filled with NaOH solution upto zero mark. The given unknown solution (mixture of a weak &
a strong acid) is transferred into a 100ml standard flask and made upto the mark with distilled water. 20ml of the
made up solution is pipetted out into a clean 100ml beaker. The solution is diluted to 20ml using distilled water. A
conductivity cell is dipped into the solution and the terminals are connected to a conductivity meter.
30


TITRATION


CALCULATION OF STRENGTH OF HCl
Volume of NaOH (V 1) = --------------- ml (titre value)
Strength of NaOH (N 1) = ---------------- N
Volume of HCl (V 2) = ------------ ml
Strength of HCl (N 2) = -------------- N

N 2 = V 1 N 1 / V 2
Strength of HCl = ---------------- N
CALCULATION OF STRENGTH OF CH3COOH
Volume of NaOH (V 1) = ------------ ml (titre value)
Strength of NaOH (N 1) = ------------ N
Volume of CH 3COOH (V 2) = ------------ ml
Strength of CH 3COOH (N 2) = ------------ N
N 2 = V 1 N 1 / V 2

Strength of CH 3COOH = ------------ N



S.No

Volume of NaOH
(ml)

Conductance (mho)

14

15

16

17
18
19
20

21
22
23
24
25
26

S.No

Volume of NaOH
(ml)

Conductance (mho)

1
2
3
4
5
6
7
8
9
10
11
12
13
31

The burette solution is added to the unknown solution in the beaker in 0.5 ml increments, the solution is
stirred using a glass rod, and the observed conductance values are read from the meter. The conductance values
show decrease in the initial values, then gradually increases and finally shows a steep increase. The titration hence
shows two end-points (i.e) I neutralization (weak acid) & II neutralization (strong acid).
The accurate end-point is obtained by plotting a graph between observed conductance Vs volume of
NaOH added.

RESULT
The strength of acids present in the given unknown solution are:
a) Strong acid = ---------------- N
b) Weak acid = -----------------N



VIVA-VOCE

1. What is weak acid?
2. How many end points are obtained from the graph? Comment two end points.
3. Why is the conductance increase in the first end point?
4. What mixture of acids used in this titration?
5. Write the neutralization reaction between CH 3COOH and NaOH.
6. What is the solution present in the conductivity cell?
7. What are strong and weak electrolytes?
8. Give an example for strong acid and weak acid.
9. What is the strong electrolyte of weak electrolyte?
10. Give an example for strong base.









32

SHORT PROCEDURE



















ROUGH GRAPH







EMF(mV)






Volume of Potassium dichromate (ml)

FAIR GRAPH









? E / ? V

Volume of Potassium dichromate (ml)




CONTENTS

TITRATION I

TITRATION II
Burette solution

Std Potassium dichromate

Std Potassium dichromate

Pipette solution

10 ml of FAS


10 ml of FAS



Additional
solution

20 ml distilled water+
10 ml of dil H 2SO 4


20 ml distilled water+
10 ml of dil H 2SO 4

End point

Sudden increase in EMF

EMF increases and decreases

Equivalent Weight of Ferrous ion = 55.85

33


Expt. No. 6 ESTIMATION OF FERROUS ION BY POTENTIOMETRIC
TITRATION

AIM
To estimate the amount of ferrous ion present in whole of the given solution potentiometrically. A standard
solution of potassium dichromate of strength -----------N is provided.

PRINCIPLE

Potentiometric titrations depend on measurement of emf between reference electrode and an indicator
electrode. When a solution of ferrous iron is titrated with a solution of potassium dichromate, the following redox
reaction takes place.

6Fe
2+
+ Cr 2O 7
2-
+ 14 H
+
? 6Fe
3+
+ 2Cr
3+
+ 7H 2O

During this titration Fe
2+
is converted in to Fe
3+
, whose concentration increases. At the end point, there
will be a sharp change due to sudden removal of all Fe
2+
ions.
The cell is set up by connecting this redox electrode with a calomel electrode as shown below:

Pt, Fe
2+
, Fe
3+
, II KCl , HgCl 2 (s), Hg

A graph between EMF measured against the volume of potassium dichromate added is drawn and the
end point is noted from the graph.

PROCEDURE

10ml of Ferrous solution is pipetted out into a 100 ml beaker. 10ml of dil.H 2SO 4 and 20ml of distilled water
are added. A platinum electrode and a calomel electrode are dipped into this solution and connected to the
potentiometer. Then 1ml of potassium dichromate is added to the solution and stirred well for 30 seconds. The
EMF is measured and the titration is continued by adding potassium dichromate in 1ml increments till five
measurements after the end point.



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?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





3


PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)
1. Fundamentals
To provide students with a solid foundation in Mathematics, Science and fundamentals of engineering,
enabling them to apply, to find solutions for engineering problems and use this knowledge to acquire higher
education
2. Core Competence
To train the students in chemistry practicals so that they apply their knowledge and training to compare,
and to analyze various engineering industrial problems to find solutions
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice this enables
them to find solutions for the real time problems in industry, and to design products
4. Professionalism
To inculcate professional and effective communication skills, leadership qualities and team spirit in the
students to make them multi-faceted personalities and develop their ability to relate engineering issues to
broader social context
5. Lifelong Learning/Ethics
To demonstrate and practice ethical and professional responsibilities in the industry and society in the
large, through commitment and lifelong learning needed for successful professional career






4


PROGRAMME OUTCOMES (POs)
To demonstrate and apply knowledge of Mathematics, Science and engineering fundamentals in the following
experiments.
1 .To estimate HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. To determine total, temporary & permanent hardness of water by EDTA method.
3. To determine DO content of water sample by Winkler?s method.
4. To determine chloride content of water sample by Argentometric method.
5. To estimate copper content of the given solution by Iodometry.
6. To determine strength of given hydrochloric acid using pH meter.
7. To determine strength of acids in a mixture of acids using conductivity meter.
8. To determine iron content of the given solution using potentiometer.
9. To estimate iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. To estimate sodium and potassium present in water using flame photometer.
11. To determine molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. To determine Pseudo first order kinetics ? ester hydrolysis.
13. To determine Corrosion experiment ? weight loss method.
14. To estimate CMC.
15. To estimate Phase change in a solid.
16. To determine strength of strong acid vs strong base using conductivity meter.











5

BS8161 - CHEMISTRY LABORATORY
SYLLABUS


? To make the student to acquire practical skills in the determination of water quality
parameters through volumetric and instrumental analysis.

? ???? ??? ???? ?? ???? ? ? ?To acquaint the students with the determination of molecular weight of a polymer by
viscometery.

LIST OF EXPERIMENTS:
1. Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. Determination of total, temporary & permanent hardness of water by EDTA method.
3. Determination of DO content of water sample by Winkler?s method.
4. Determination of chloride content of water sample by Argentometric method.
5. Estimation of copper content of the given solution by Iodometry.
6. Determination of strength of given hydrochloric acid using pH meter.
7. Determination of strength of acids in a mixture of acids using conductivity meter.
8. Estimation of iron content of the given solution using potentiometer.
9. Estimation of iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. Estimation of sodium and potassium present in water using flame photometer.
11. Determination of molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. Pseudo first order kinetics ? ester hydrolysis.
13. Corrosion experiment ? weight loss method.
14. Determination of CMC.
15. Phase change in a solid.
16. Conductometric titration of strong acid vs strong base.




? The students will be outfitted with hands-on knowledge in the quantitative chemical
analysis of water quality related parameters.
COURSE OBJECTIVES
COURSE OUTCOMES
6


INDEX [ SEMESTER ? I ]


S.No.



Date


Experiment

Date of
submission



Mark


Signature

1.

Estimation of HCl using Na 2CO 3 as
primary standard and Determination of
alkalinity in water sample.



2.


Determination of total, temporary &
permanent hardness of water by EDTA
method.



3.


Determination of chloride content of water
sample by argentometric method.



4.


Determination of strength of given
hydrochloric acid using pH meter.



5.


Determination of strength of acids in a
mixture of acids using conductivity meter.



6.


Estimation of iron content of the given
solution using potentiometer.



7.





Conductometric titration of strong acid Vs
strong base.



8.



Estimation of copper content of the given
solution by Iodometry


9.
Estimation of sodium and potassium
present in water using flame photometer




7




CONTENTS


S.No.


NAME OF EXPERIMENT

PAGE
No.
SEMESTER - I
1.
Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in
water sample.
09
2. Determination of total, temporary & permanent hardness of water by EDTA method. 15
3. Determination of chloride content of water sample by Argentometric method. 21
4. Determination of strength of given hydrochloric acid using pH meter. 25
5. Determination of strength of acids in a mixture of acids using conductivity meter. 29
6. Estimation of iron content of the given solution using potentiometer. 33
7. Conductometric titration of strong acid Vs strong base.

39


42

8


Estimation of copper content of the given solution by Iodometry 43
9 Estimation of sodium and potassium present in water using flame photometer 47






8



SHORT PROCEDURE:

CONTENTS
TITRATION
Estimation of alkalinity in water sample
(Std HCl Vs water sample)

Burette solution

Std. HCl


Pipette solution

Water sample


Indicator


(i) Phenolphthalein
(ii) Methyl orange


End point

(i) Disappearance of pink colour
(ii) Appearance of reddish orange colour






Relationship
between P &M
Nature of alkalinity
Amount of individual
alkalinities
OH
-
HCO 3
-


CO 3
2-

P = M

only OH
-

P or M

?
0.0

0.0


2P = M

only CO 3
2-


2P or M


0.0


0.0


?

P =0, M?0

only HCO 3
-



M



0.0



?

0.0


2P > M


OH
-
&CO 3
2-


OH
-
= 2P-M
CO 3
2-
= 2(M-P)


?

0.0

?

P < ? M




HCO 3
-
&CO 3
2-


HCO 3
-
= M-2P
CO 3
2-
= 2P

0.0 ? ?




9





Expt. No. 1 DETERMINATION OF ALKALINITY IN WATER
AIM
To determine the type and amounts of alkalinity in the given water sample. A standard solution of Na 2CO 3
of strength ____N is given.

PRINCIPLE
Alkalinity in water is due to the presence of soluble hydroxides, bicarbonates and carbonates.
Determination of various types and amounts of alkalinity is easily carried out by titration with standard HCl
employing the indicators phenolphthalein and methyl orange independently or in succession.

The following reactions occur when different types of alkalinity are neutralized with acid.

OH
?
+ H
+
? H 2O completed at pH 8.2-9.0 ----- (1)

CO 3
2 ?
+ H
+
? HCO 3
?
----- (2)

HCO 3
?
+ H
+
? (H 2CO 3) ? H 2O + CO 2, completed at pH 4.2-5.5 ----- (3)

Neutralisation (1) & (2) will be notified by phenolphthalein end-point while all the three will be

accounted by
methyl orange end-point. Bicarbonate in eqn. (3) may be due to the existence of soluble free bicarbonate salts and
bicarbonates resulting from half neutralization of soluble carbonates (eqn. (2))

Various steps to be followed

a) A known volume of water sample is titrated against std. HCl using first phenolphthalein indicator till
end-point (P) and the titration is continued without break using methyl orange indicator till the end-
point (M).



10


Titration

Estimation of Alkalinity in water sample

Standard HCl Vs Water sample Indicator: 1. Phenolphthalein
2. Methyl Orange


S.No.
Volume
of water
sample (ml)
Burette Reading
Concordant value

Initial Phenolphthalein End
Point (P)
Methyl Orange End
Point (M)

1

2






CALCULATION

Hydroxide ion alkalinity
Volume of HCl (2P-M) = ???????ml

Strength of HCl = ???????? N

Volume of water sample = ???????...ml

Strength of water sample = Volume of HCl (2P-M) x Strength of HCl
Volume of water sample

=

? Hydroxide ion alkalinity in terms of
CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ??????.mg/l







11




b) From the magnitudes of the P & M, the nature of alkalinity can be arrived as follows:

(i) P = M => Presence of only OH
-

(ii) 2P = M => Presence of only CO 3
2-

(iii) P =0, M=0 => Presence of only HCO 3
-
(iv) 2P > M => Presence of OH
-
& CO 3
2-
(v) 2P < M => Presence of HCO 3
-
& CO 3
2-

(Mixture of OH
-
& HCO3
-
is not listed since they do not exist together and are considered equivalent to CO 3
2-
).

PROCEDURE
TITRATION
ESTIMATION OF ALKALINITY IN WATER SAMPLE

Exactly 20 ml of water sample is pipetted out into a clean conical flask. Few drops of phenolphthalein
indicator are added and titrated against a standardized HCl taken in the burette. The end point is the
disappearance of pink colour, which is noted as P. Few drops of methyl orange indicator is added to the same
solution. The solution turns to yellow. The titration is continued further by adding same HCl without break till the
end point is reached. The end point is the colour change from yellow to reddish orange.

The experiment is repeated to get concordant values. From the magnitudes of P & M values, the type of
alkalinity present in the water sample is inferred and the individual amounts are calculated and reported.










12


Carbonate ion alkalinity

Volume of HCl 2 (M ? P) = ??? ????????ml

Strength of HCl = ??.?????..???...N

Volume of water sample =........................................ml

Strength of water sample = Volume of HCl 2 (M ? P) x Strength of HCl
Volume of water sample

= ???????????.. N




? Carbonate ion alkalinity
in terms of CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ???????????mg/l

















13





RESULT

1) The type of alkalinity present in the water sample = -------------------------ions.

2) The individual amounts of alkalinity present in the water sample:
Hydroxide ion alkalinity

= ----------------- ppm
Carbonate ion alkalinity = ------------------ ppm
Bicarbonate ion alkalinity = ----------------- ppm





VIVA-VOCE


1. What is meant by alkalinity?
2. What are the ions responsible for alkalinity?
3. Why OH
-
and HCO 3
?
ions cannot exist together in water?
4. What are the ions responsible for alkalinity when 2P > M?
5. What is the pH range for both in acidic and basic solutions?
6. What is the colour of phenolphthalein in an acid and in an alkaline solution?
7. What is the purpose of using two indicators in same titration?
8. What are the possible combinations of ions for alkalinity?
9. How is the amount of alkalinity expressed?
10. What are the types of indicator used in this experiment?







14

SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II TITRATION III
Standardisation of
EDTA
(EDTA Vs Std
Hard water)
Determination of
total hardness
(Std EDTA Vs Hard
water sample)
Determination of
permanent hardness
(Std EDTA Vs Boiled
Hard water sample)

Burette solution

EDTA solution

EDTA solution

EDTA solution

Pipette solution

20ml Std. hard water

20 ml hard water sample

20ml boiled hard water sample

Indicator

2 drops of EBT

2 drops of EBT

2 drops of EBT

Additional soln.


Ammoniacal Buffer
solution (5ml)

Ammoniacal Buffer solution
(5ml)

Ammoniacal Buffer solution
(5ml)
End point Wine - red to Steel blue Wine - red to steel blue Wine - red to Steel blue




STANDARDISATION OF EDTA
Titration - I
Std. HARD WATER Vs EDTA Indicator: EBT

S. No.
Volume of std hard
water (ml)
Burette Reading Volume of
EDTA
(V 1) (ml)
Concordant value

Initial

Final



Volume of std .hard water taken = 20 ml
Volume of EDTA consumed (V 1) = --------------- ml
1 ml of std.hard water = 1mg of CaCO 3
20 ml of std hard water = 20 mg of CaCO 3

V 1 ml of EDTA solution containing 20 mg of CaCO 3
1 ml of EDTA solution = 20 / V 1 mg of CaCO 3
= -----------------------mg of CaCO 3


15

Expt. No. 2 DETERMINATION OF TOTAL, TEMPORARY AND
PERMANENT HARDNESS OF WATER

AIM
To estimate the amount of total, temporary & permanent hardness in the given sample of water.

PRINCIPLE
The estimation is based on the complexometric titration.

(i) Total hardness of water is estimated by titrating against EDTA using EBT indicator.
EBT+M ?[EBT-M] (unstable complex)
(EBT-M) (Unstable complex) +EDTA ? [EDTA-M] (stable complex) +EBT
EBT indicator forms wine- red colored complex with metal ions present in water. On addition of EDTA
metal ions preferably forms complexes with EDTA and steel blue EBT indicator is set free. Therefore
change of colour from wine- red to steel blue denotes the end point.

(ii) Temporary hardness is removed by boiling the water.
Ca (HCO 3) 2 ? CaCO 3 +CO 2 ?+H 2O
Mg (HCO 3) 2 ? Mg(OH) 2 +2CO 2 ?
The precipitate is filtered and the remaining permanent hardness is estimated using EDTA.

PROCEDURE

TITRATION ? I
STANDARDISATION OF EDTA

Pipette out 20ml of standard hard water into a 250ml conical flask. Add 5ml of buffer solution and 3
drops of eriochrome black T indictor. Titrate the solution with EDTA from the burette until the colour
changes from wine- red to steel blue at the end point. Repeat the titration for concordant values. Let the
titre value be V 1ml.


16


Titration-II
SAMPLE HARD WATER Vs Std EDTA Indicator: EBT

S.No. Volume of sample
hard water (ml)
Burette Reading Volume of
EDTA
(V 2) (ml)
Concordant value

Initial

Final




CALCULATION

Calculation of total hardness


Volume of EDTA consumed (V 2) = ------------------------- ml
1ml of EDTA = 20 / V 1 mg of CaCO 3
V 2 ml of EDTA = 20 / V 1 x V 2 mg of CaCO 3

( i.e), If 20ml of sample hard water contains 20 x V 2 mg of CaCO 3 / V 1

Then 1000ml of water sample = 20 x V 2 x 1000 / V 1 x 20 mg of CaCO 3

= 1000 x V 2 / V 1 mg of CaCO3

Total hardness of given water sample = ---------------------ppm









17



DETERMINATION OF TOTAL HARDNESS

Pipette out 20ml of sample hard water into a clean conical flask. Add 5ml of buffer solution and 4 -5
drops of Eriochrome black -T indicator. Titrate the wine - red coloured solution with EDTA from the burette until
the colour steel blue appears at the end point. Repeat the titration for concordant values. Let the titre value be
V 2ml.



DETERMINATION OF PERMANENT HARDNESS

Take 100ml of hard water sample in a 500ml beaker and boil gently for about 1hour. Cool, filter it into a
100ml standard flask and make the volume up to the mark. Take 20ml of this solution and proceed it in the same
way as in titration (I). The volume of EDTA consumed corresponds to the permanent hardness of the water
sample. Let the titre value be V 3ml. Temporary hardness is calculated by subtracting permanent hardness from
total hardness.





















18




DETERMINATION OF PERMANENT HARDNESS
BOILED SAMPLE WATER Vs Std. EDTA Indicator: EBT


S.No.
Volume of boiled
hard water (ml)
Burette Reading (ml) Volume of
EDTA
(ml)

Concordant value

Initial Final



CALCULATION OF PERMANENT HARDNESS


Volume of EDTA consumed V 3 = ---------------------ml

1ml of EDTA = 20 / V 1 mg of CaCO 3

V 3ml of EDTA = 20 / V 1 x V 3 mg of CaCO 3

(i.e) 20 ml of boiled sample hard water = 20 / V 1 x V 3 mg of CaCO 3

Then 1000ml of boiled water sample = 20 / V 1 x V 3 / 20 * 1000mg of CaCO 3

= 1000 x V 3 / V 1 mg of CaCO 3

permanent hardness of boiled water sample = -----------------ppm

Temporary hardness of the given water sample = Total hardness ? Permanent hardness

= ------------------ppm

19







RESULT

(i) Total hardness of the given sample water = -------------- ppm.
(ii) Permanent hardness of the given sample water = --------------- ppm.
(iii) Temporary hardness of the given sample water = ----------------ppm.







VIVA-VOCE

1. Define ? Hard water
2. What is the structure of EDTA?
3. How will you calculate temporary hardness?
4. What is the role of the buffer in EDTA titration?
5. What is the permissible limit of hardness in drinking water?
6. Name the hardness producing ions present in water.
7. Name two salts which are responsible for temporary hardness.
8. Why is CaCO 3 taken as the standard?
9. Write the expansion of EDTA.
10. What is meant by EBT?











20





SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II
Standardisation of
AgNO 3
Estimation of Chloride
Burette solution

AgNO 3 solution

Std. AgNO 3 solution

Pipette solution

20ml std KCl solution

20 ml water sample

Indicator

1ml K 2CrO 4

1ml K 2CrO 4


End point

yellow to reddish brown

yellow to reddish brown

Titration I
Std. AgNO3 Vs KCl Indicator: Potassium Chromate













CALCULATION

Volume of KCl (V 1) = ------- ml

Strength of KCl (N 1) = ------- N

Volume of Silver Nitrate (V 2) = -------- ml

Strength of Siver Nitrate V 1N 1
N 2 =
V 1

= --------------------- N

S.No.
Volume of KCl
(ml)
Burette Reading (ml)
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

21




Expt.No. 3 ESTIMATION OF CHLORIDE CONTENT IN WATER
(ARGENTOMETRIC METHOD)
AIM
To estimate the amount of chloride present in given water sample by Argentometric method (Mohr?s
method). You are provided with standard solution of NaCl of strength --------N and a approximately N/10 solution of
Silver nitrate.

PRINCIPLE
The Chloride ion in the form of NaCl, KCl, CaCl 2, MgCl 2 etc., present in the water sample can be estimated
by Argentometric method or known as Mohr?s method. It is an example for precipitation titration. The reaction
between std. Sodium chloride and Silver nitrate is given below.
AgNO 3 + NaCl ? AgCl ? + NaNO 3
The completion of reaction can be observed by employing potassium chromate as the indicator. The end
point is the colour change from yellow to reddish brown due to the following reaction.
2AgNO 3 + K 2CrO 4 ? Ag 2CrO 4 ? + 2KNO 3
Potassium chromate indicator will not be precipitated as silver chromate until all the chlorides in the solution
have been precipitated as AgCl Since a precipitation reaction takes place in preference, this reaction takes place
only at the end point.

PROCEDURE
TITRATION I: STANDARDISATION OF SILVER NITRATE
Pipette out 20ml of standard sodium or potassium chloride solution into a clean conical flask. Add 1ml of 5%
K 2CrO 4 indicator, as the solution turns yellow in colour. Titrate it against silver nitrate solution taken in the burette.
Observe the nearness of the end point through the formation of coagulated silver chloride precipitate at the bottom
of the flask. Now add the silver nitrate drop by drop until the solution gets a faint reddish brown tinge. Repeat the
titration for concordant value. Let the volume of silver nitrate be V 2ml.





22






TITRATION - II

Std AgNO3 Vs WATER SAMPLE Indicator: Potassium Chromate













CALCULATION

Volume of Silver Nitrate (V 3) = ------------ ml

Strength of Siver Nitrate (N 3) = ------------- N

Volume of Water sample (V 4) = -------------- ml

Strength of Water sample V 3 N 3
(N 4) =
V 4

= ----------------- N

Amount of Chloride ion present in 1000 ml of the water sample = Equivalent mass of HCl X 1000


= N 4 x 35.46 x 1000


= -----------------mg/l







S.No.
Volume of water
sample (ml)
Burette Reading
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

23





TITRATION - II
ESTIMATION OF CHLORIDE ION

Pipette out 40 ml of the given water sample into a clean conical flask.To this sample add 1ml of 5% K 2CrO 4
indicator and titrate it against the standardized silver nitrate solution taken in the burette and continue the titration
until the solution produces a reddish brown colour. Note down the end point and repeat the titration for
concordance. Let the volume be V 3ml.







RESULT

The amount of chloride ion present in the water sample = ----------------- mg/l.




VIVA-VOCE

1. Why is this method known as Argentometric method?
2.
What is the chemical reaction between AgNO 3 and Cl
-
ions present in water?

3.
What is the form of Chloride ion present in water?

4. What is the reaction between AgNO 3 and K 2CrO 4 ?
5. What is the name of the method used in this titration?
6. Name the link solution used in the determination.
7. Name the solution used to standardize AgNO 3.
8. What is the indicator used in the determination?
9. How will you calculate the amount of chloride ion in the given solution?
10. What is the colour change in the titration?




24




SHORT PROCEDURE


CONTENTS

TITRATION I

TITRATION II
Burette solution

Std Sodium Hydroxide

Std Sodium Hydroxide

Pipette solution

20 ml hydrochloric acid 20 ml hydrochloric acid
Additional solution


20 ml distilled water

20 ml distilled water


End point



Sudden increase in pH
pH gradual increase

Equivalent Weight of HCl = 36.5







ROUGH GRAPH FAIR GRAPH











pH
? pH/ ? V





Volume of NaOH
(ml)
Volume of NaOH
(ml)





25



Expt. No. 4 DETERMINATION OF STRENGTH OF HCl by pH METRY

AIM
To determine the strength of given HCl by pH metry. A standard solution of 0.1N NaOH is provided.

PRINCIPLE
The pH of a solution is related to H
+
ion concentration by the following formula.

. pH = -log [ H
+
]

pH of a solution is indirectly related to H
+
ion concentration. When NaOH is added slowly to HCl, H
+
ions
get neutralized by OH
-
ions. The pH increases slowly.

H
+
+ Cl
-
+ Na
+
+ OH
-
? Na
+
+ Cl
-
+H 2O

When all H
+
ions of HCl are neutralized at the end point, addition of NaOH causes high increase in pH
because of the addition of excess OH
-
ions.

MATERIALS REQUIRED
pH meter, Glass electrode, Burette, Pipette, Std.NaOH, approximately N/10 HCl .

PROCEDURE

The burette is washed with distilled water, rinsed with the given std. Sodium hydroxide and filled with the
same solution. Exactly 10ml of the given HCl solution is pipetted out into a clean beaker. It is then diluted to 50ml
with distilled water. A glass electrode is dipped into the solution and its terminals are connected to a pH meter.

26

TITRATION - I
S.No Volume of
NaOH (ml)
pH
1

2

3

4

5

6

7

8

9

10


TITRATION - II



CALCULATION

Volume of NaOH (V 1) = ------------------- ml ( titre value)
Strength of NaOH (N 1) = ------------------- N
Volume of HCl (V 2) = ------------------ml
Strength of HCl (N 2) = ------------------ N
N 2 = V 1 N 1 / V 2
Strength of HCl = -------------------- N
Amount of HCl present in 1000ml of the given solution = Strength x equivalent weight of HCl
= ------------------ X 36.5
= --------------------- g
S.No Volume of
NaOH (ml)
pH
11

12

13

14

15

16

17

18

19

20

S.No
Volume of
NaOH (ml)
pH ?pH ?V ?pH / ?V
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
27



Now NaOH is gradually added from the burette to HCl taken in the beaker. pH of the solution is noted for
each addition of NaOH. This process is continued until 5 readings are taken after the end point.
A fair titration is performed to find the exact end point.





RESULT

(i) Strength of the given HCl solution = ---------------- N
(ii) Amount of HCl present in a litre of the solution = ---------------- g


VIVA-VOCE

1. What is meant by pH?
2. What is the name of the reference electrode used ?
3. Why does pH value increase suddenly at the end point?
4. What is the indicator used in the titration?
5. What is the pH range of human blood?
6. What is the unit of pH?
7. How will you calculate the amount of HCl?
8. How is glass electrode represented?
9. Why is glass electrode known as ion selective electrode?
10. What is the chemical reaction involved in this titration?





28




SHORT PROCEDURE


CONTENTS
TITRATION
Burette solution

Std Sodium Hydroxide

Pipette solution

20 ml mixture of acid (HCl+ CH 3COOH)


Additional solution

20 ml distilled water


End point

Conductivity decreases-slowly increases-Sudden increase



Equivalent Weight of HCl = 36.5


Equivalent Weight of CH 3COOH = 60



MODEL GRAPH


Conductance
Volume of NaOH
Mixture of Acids






29




Expt. No. 5 CONDUCTOMETRIC TITRATION OF MIXTURE
OF ACIDS

AIM
To determine the amount of a strong acid and a weak acid present in the given solution.

PRINCIPLE

Solution of electrolytes conducts electricity due to the presence of ions. Since specific conductance of a
solution is proportional to the concentration of ions in it, conductance of the solution is measured during the titration.

HCl + NaOH ? NaCl + H 2O (I neutralization)

CH 3COOH + NaOH ? CH 3COONa + H 2O (II neutralization)

When a solution of HCl is treated with NaOH the fast moving hydrogen ions are progressively replaced by
slow moving sodium ions. As a result conductance of the solution decreases. This decrease will take place until the
first neutralisation point is reached. Further addition of alkali results in formation of sodium acetate.

Since sodium acetate is stronger than acetic acid conductivity slowly increases until all acetic acid is
completely neutralized.(II Neutralisation) This is due to the presence of fast moving OH
-
ions. Anymore addition of
alkali increases the conductance sharply.

PROCEDURE
The burette is filled with NaOH solution upto zero mark. The given unknown solution (mixture of a weak &
a strong acid) is transferred into a 100ml standard flask and made upto the mark with distilled water. 20ml of the
made up solution is pipetted out into a clean 100ml beaker. The solution is diluted to 20ml using distilled water. A
conductivity cell is dipped into the solution and the terminals are connected to a conductivity meter.
30


TITRATION


CALCULATION OF STRENGTH OF HCl
Volume of NaOH (V 1) = --------------- ml (titre value)
Strength of NaOH (N 1) = ---------------- N
Volume of HCl (V 2) = ------------ ml
Strength of HCl (N 2) = -------------- N

N 2 = V 1 N 1 / V 2
Strength of HCl = ---------------- N
CALCULATION OF STRENGTH OF CH3COOH
Volume of NaOH (V 1) = ------------ ml (titre value)
Strength of NaOH (N 1) = ------------ N
Volume of CH 3COOH (V 2) = ------------ ml
Strength of CH 3COOH (N 2) = ------------ N
N 2 = V 1 N 1 / V 2

Strength of CH 3COOH = ------------ N



S.No

Volume of NaOH
(ml)

Conductance (mho)

14

15

16

17
18
19
20

21
22
23
24
25
26

S.No

Volume of NaOH
(ml)

Conductance (mho)

1
2
3
4
5
6
7
8
9
10
11
12
13
31

The burette solution is added to the unknown solution in the beaker in 0.5 ml increments, the solution is
stirred using a glass rod, and the observed conductance values are read from the meter. The conductance values
show decrease in the initial values, then gradually increases and finally shows a steep increase. The titration hence
shows two end-points (i.e) I neutralization (weak acid) & II neutralization (strong acid).
The accurate end-point is obtained by plotting a graph between observed conductance Vs volume of
NaOH added.

RESULT
The strength of acids present in the given unknown solution are:
a) Strong acid = ---------------- N
b) Weak acid = -----------------N



VIVA-VOCE

1. What is weak acid?
2. How many end points are obtained from the graph? Comment two end points.
3. Why is the conductance increase in the first end point?
4. What mixture of acids used in this titration?
5. Write the neutralization reaction between CH 3COOH and NaOH.
6. What is the solution present in the conductivity cell?
7. What are strong and weak electrolytes?
8. Give an example for strong acid and weak acid.
9. What is the strong electrolyte of weak electrolyte?
10. Give an example for strong base.









32

SHORT PROCEDURE



















ROUGH GRAPH







EMF(mV)






Volume of Potassium dichromate (ml)

FAIR GRAPH









? E / ? V

Volume of Potassium dichromate (ml)




CONTENTS

TITRATION I

TITRATION II
Burette solution

Std Potassium dichromate

Std Potassium dichromate

Pipette solution

10 ml of FAS


10 ml of FAS



Additional
solution

20 ml distilled water+
10 ml of dil H 2SO 4


20 ml distilled water+
10 ml of dil H 2SO 4

End point

Sudden increase in EMF

EMF increases and decreases

Equivalent Weight of Ferrous ion = 55.85

33


Expt. No. 6 ESTIMATION OF FERROUS ION BY POTENTIOMETRIC
TITRATION

AIM
To estimate the amount of ferrous ion present in whole of the given solution potentiometrically. A standard
solution of potassium dichromate of strength -----------N is provided.

PRINCIPLE

Potentiometric titrations depend on measurement of emf between reference electrode and an indicator
electrode. When a solution of ferrous iron is titrated with a solution of potassium dichromate, the following redox
reaction takes place.

6Fe
2+
+ Cr 2O 7
2-
+ 14 H
+
? 6Fe
3+
+ 2Cr
3+
+ 7H 2O

During this titration Fe
2+
is converted in to Fe
3+
, whose concentration increases. At the end point, there
will be a sharp change due to sudden removal of all Fe
2+
ions.
The cell is set up by connecting this redox electrode with a calomel electrode as shown below:

Pt, Fe
2+
, Fe
3+
, II KCl , HgCl 2 (s), Hg

A graph between EMF measured against the volume of potassium dichromate added is drawn and the
end point is noted from the graph.

PROCEDURE

10ml of Ferrous solution is pipetted out into a 100 ml beaker. 10ml of dil.H 2SO 4 and 20ml of distilled water
are added. A platinum electrode and a calomel electrode are dipped into this solution and connected to the
potentiometer. Then 1ml of potassium dichromate is added to the solution and stirred well for 30 seconds. The
EMF is measured and the titration is continued by adding potassium dichromate in 1ml increments till five
measurements after the end point.



34


ROUGH TITRATION



S.No.

Volume of dichromate (ml)

EMF (mV)


1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.





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DEPARTMENT OF
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I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





3


PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)
1. Fundamentals
To provide students with a solid foundation in Mathematics, Science and fundamentals of engineering,
enabling them to apply, to find solutions for engineering problems and use this knowledge to acquire higher
education
2. Core Competence
To train the students in chemistry practicals so that they apply their knowledge and training to compare,
and to analyze various engineering industrial problems to find solutions
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice this enables
them to find solutions for the real time problems in industry, and to design products
4. Professionalism
To inculcate professional and effective communication skills, leadership qualities and team spirit in the
students to make them multi-faceted personalities and develop their ability to relate engineering issues to
broader social context
5. Lifelong Learning/Ethics
To demonstrate and practice ethical and professional responsibilities in the industry and society in the
large, through commitment and lifelong learning needed for successful professional career






4


PROGRAMME OUTCOMES (POs)
To demonstrate and apply knowledge of Mathematics, Science and engineering fundamentals in the following
experiments.
1 .To estimate HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. To determine total, temporary & permanent hardness of water by EDTA method.
3. To determine DO content of water sample by Winkler?s method.
4. To determine chloride content of water sample by Argentometric method.
5. To estimate copper content of the given solution by Iodometry.
6. To determine strength of given hydrochloric acid using pH meter.
7. To determine strength of acids in a mixture of acids using conductivity meter.
8. To determine iron content of the given solution using potentiometer.
9. To estimate iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. To estimate sodium and potassium present in water using flame photometer.
11. To determine molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. To determine Pseudo first order kinetics ? ester hydrolysis.
13. To determine Corrosion experiment ? weight loss method.
14. To estimate CMC.
15. To estimate Phase change in a solid.
16. To determine strength of strong acid vs strong base using conductivity meter.











5

BS8161 - CHEMISTRY LABORATORY
SYLLABUS


? To make the student to acquire practical skills in the determination of water quality
parameters through volumetric and instrumental analysis.

? ???? ??? ???? ?? ???? ? ? ?To acquaint the students with the determination of molecular weight of a polymer by
viscometery.

LIST OF EXPERIMENTS:
1. Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. Determination of total, temporary & permanent hardness of water by EDTA method.
3. Determination of DO content of water sample by Winkler?s method.
4. Determination of chloride content of water sample by Argentometric method.
5. Estimation of copper content of the given solution by Iodometry.
6. Determination of strength of given hydrochloric acid using pH meter.
7. Determination of strength of acids in a mixture of acids using conductivity meter.
8. Estimation of iron content of the given solution using potentiometer.
9. Estimation of iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. Estimation of sodium and potassium present in water using flame photometer.
11. Determination of molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. Pseudo first order kinetics ? ester hydrolysis.
13. Corrosion experiment ? weight loss method.
14. Determination of CMC.
15. Phase change in a solid.
16. Conductometric titration of strong acid vs strong base.




? The students will be outfitted with hands-on knowledge in the quantitative chemical
analysis of water quality related parameters.
COURSE OBJECTIVES
COURSE OUTCOMES
6


INDEX [ SEMESTER ? I ]


S.No.



Date


Experiment

Date of
submission



Mark


Signature

1.

Estimation of HCl using Na 2CO 3 as
primary standard and Determination of
alkalinity in water sample.



2.


Determination of total, temporary &
permanent hardness of water by EDTA
method.



3.


Determination of chloride content of water
sample by argentometric method.



4.


Determination of strength of given
hydrochloric acid using pH meter.



5.


Determination of strength of acids in a
mixture of acids using conductivity meter.



6.


Estimation of iron content of the given
solution using potentiometer.



7.





Conductometric titration of strong acid Vs
strong base.



8.



Estimation of copper content of the given
solution by Iodometry


9.
Estimation of sodium and potassium
present in water using flame photometer




7




CONTENTS


S.No.


NAME OF EXPERIMENT

PAGE
No.
SEMESTER - I
1.
Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in
water sample.
09
2. Determination of total, temporary & permanent hardness of water by EDTA method. 15
3. Determination of chloride content of water sample by Argentometric method. 21
4. Determination of strength of given hydrochloric acid using pH meter. 25
5. Determination of strength of acids in a mixture of acids using conductivity meter. 29
6. Estimation of iron content of the given solution using potentiometer. 33
7. Conductometric titration of strong acid Vs strong base.

39


42

8


Estimation of copper content of the given solution by Iodometry 43
9 Estimation of sodium and potassium present in water using flame photometer 47






8



SHORT PROCEDURE:

CONTENTS
TITRATION
Estimation of alkalinity in water sample
(Std HCl Vs water sample)

Burette solution

Std. HCl


Pipette solution

Water sample


Indicator


(i) Phenolphthalein
(ii) Methyl orange


End point

(i) Disappearance of pink colour
(ii) Appearance of reddish orange colour






Relationship
between P &M
Nature of alkalinity
Amount of individual
alkalinities
OH
-
HCO 3
-


CO 3
2-

P = M

only OH
-

P or M

?
0.0

0.0


2P = M

only CO 3
2-


2P or M


0.0


0.0


?

P =0, M?0

only HCO 3
-



M



0.0



?

0.0


2P > M


OH
-
&CO 3
2-


OH
-
= 2P-M
CO 3
2-
= 2(M-P)


?

0.0

?

P < ? M




HCO 3
-
&CO 3
2-


HCO 3
-
= M-2P
CO 3
2-
= 2P

0.0 ? ?




9





Expt. No. 1 DETERMINATION OF ALKALINITY IN WATER
AIM
To determine the type and amounts of alkalinity in the given water sample. A standard solution of Na 2CO 3
of strength ____N is given.

PRINCIPLE
Alkalinity in water is due to the presence of soluble hydroxides, bicarbonates and carbonates.
Determination of various types and amounts of alkalinity is easily carried out by titration with standard HCl
employing the indicators phenolphthalein and methyl orange independently or in succession.

The following reactions occur when different types of alkalinity are neutralized with acid.

OH
?
+ H
+
? H 2O completed at pH 8.2-9.0 ----- (1)

CO 3
2 ?
+ H
+
? HCO 3
?
----- (2)

HCO 3
?
+ H
+
? (H 2CO 3) ? H 2O + CO 2, completed at pH 4.2-5.5 ----- (3)

Neutralisation (1) & (2) will be notified by phenolphthalein end-point while all the three will be

accounted by
methyl orange end-point. Bicarbonate in eqn. (3) may be due to the existence of soluble free bicarbonate salts and
bicarbonates resulting from half neutralization of soluble carbonates (eqn. (2))

Various steps to be followed

a) A known volume of water sample is titrated against std. HCl using first phenolphthalein indicator till
end-point (P) and the titration is continued without break using methyl orange indicator till the end-
point (M).



10


Titration

Estimation of Alkalinity in water sample

Standard HCl Vs Water sample Indicator: 1. Phenolphthalein
2. Methyl Orange


S.No.
Volume
of water
sample (ml)
Burette Reading
Concordant value

Initial Phenolphthalein End
Point (P)
Methyl Orange End
Point (M)

1

2






CALCULATION

Hydroxide ion alkalinity
Volume of HCl (2P-M) = ???????ml

Strength of HCl = ???????? N

Volume of water sample = ???????...ml

Strength of water sample = Volume of HCl (2P-M) x Strength of HCl
Volume of water sample

=

? Hydroxide ion alkalinity in terms of
CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ??????.mg/l







11




b) From the magnitudes of the P & M, the nature of alkalinity can be arrived as follows:

(i) P = M => Presence of only OH
-

(ii) 2P = M => Presence of only CO 3
2-

(iii) P =0, M=0 => Presence of only HCO 3
-
(iv) 2P > M => Presence of OH
-
& CO 3
2-
(v) 2P < M => Presence of HCO 3
-
& CO 3
2-

(Mixture of OH
-
& HCO3
-
is not listed since they do not exist together and are considered equivalent to CO 3
2-
).

PROCEDURE
TITRATION
ESTIMATION OF ALKALINITY IN WATER SAMPLE

Exactly 20 ml of water sample is pipetted out into a clean conical flask. Few drops of phenolphthalein
indicator are added and titrated against a standardized HCl taken in the burette. The end point is the
disappearance of pink colour, which is noted as P. Few drops of methyl orange indicator is added to the same
solution. The solution turns to yellow. The titration is continued further by adding same HCl without break till the
end point is reached. The end point is the colour change from yellow to reddish orange.

The experiment is repeated to get concordant values. From the magnitudes of P & M values, the type of
alkalinity present in the water sample is inferred and the individual amounts are calculated and reported.










12


Carbonate ion alkalinity

Volume of HCl 2 (M ? P) = ??? ????????ml

Strength of HCl = ??.?????..???...N

Volume of water sample =........................................ml

Strength of water sample = Volume of HCl 2 (M ? P) x Strength of HCl
Volume of water sample

= ???????????.. N




? Carbonate ion alkalinity
in terms of CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ???????????mg/l

















13





RESULT

1) The type of alkalinity present in the water sample = -------------------------ions.

2) The individual amounts of alkalinity present in the water sample:
Hydroxide ion alkalinity

= ----------------- ppm
Carbonate ion alkalinity = ------------------ ppm
Bicarbonate ion alkalinity = ----------------- ppm





VIVA-VOCE


1. What is meant by alkalinity?
2. What are the ions responsible for alkalinity?
3. Why OH
-
and HCO 3
?
ions cannot exist together in water?
4. What are the ions responsible for alkalinity when 2P > M?
5. What is the pH range for both in acidic and basic solutions?
6. What is the colour of phenolphthalein in an acid and in an alkaline solution?
7. What is the purpose of using two indicators in same titration?
8. What are the possible combinations of ions for alkalinity?
9. How is the amount of alkalinity expressed?
10. What are the types of indicator used in this experiment?







14

SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II TITRATION III
Standardisation of
EDTA
(EDTA Vs Std
Hard water)
Determination of
total hardness
(Std EDTA Vs Hard
water sample)
Determination of
permanent hardness
(Std EDTA Vs Boiled
Hard water sample)

Burette solution

EDTA solution

EDTA solution

EDTA solution

Pipette solution

20ml Std. hard water

20 ml hard water sample

20ml boiled hard water sample

Indicator

2 drops of EBT

2 drops of EBT

2 drops of EBT

Additional soln.


Ammoniacal Buffer
solution (5ml)

Ammoniacal Buffer solution
(5ml)

Ammoniacal Buffer solution
(5ml)
End point Wine - red to Steel blue Wine - red to steel blue Wine - red to Steel blue




STANDARDISATION OF EDTA
Titration - I
Std. HARD WATER Vs EDTA Indicator: EBT

S. No.
Volume of std hard
water (ml)
Burette Reading Volume of
EDTA
(V 1) (ml)
Concordant value

Initial

Final



Volume of std .hard water taken = 20 ml
Volume of EDTA consumed (V 1) = --------------- ml
1 ml of std.hard water = 1mg of CaCO 3
20 ml of std hard water = 20 mg of CaCO 3

V 1 ml of EDTA solution containing 20 mg of CaCO 3
1 ml of EDTA solution = 20 / V 1 mg of CaCO 3
= -----------------------mg of CaCO 3


15

Expt. No. 2 DETERMINATION OF TOTAL, TEMPORARY AND
PERMANENT HARDNESS OF WATER

AIM
To estimate the amount of total, temporary & permanent hardness in the given sample of water.

PRINCIPLE
The estimation is based on the complexometric titration.

(i) Total hardness of water is estimated by titrating against EDTA using EBT indicator.
EBT+M ?[EBT-M] (unstable complex)
(EBT-M) (Unstable complex) +EDTA ? [EDTA-M] (stable complex) +EBT
EBT indicator forms wine- red colored complex with metal ions present in water. On addition of EDTA
metal ions preferably forms complexes with EDTA and steel blue EBT indicator is set free. Therefore
change of colour from wine- red to steel blue denotes the end point.

(ii) Temporary hardness is removed by boiling the water.
Ca (HCO 3) 2 ? CaCO 3 +CO 2 ?+H 2O
Mg (HCO 3) 2 ? Mg(OH) 2 +2CO 2 ?
The precipitate is filtered and the remaining permanent hardness is estimated using EDTA.

PROCEDURE

TITRATION ? I
STANDARDISATION OF EDTA

Pipette out 20ml of standard hard water into a 250ml conical flask. Add 5ml of buffer solution and 3
drops of eriochrome black T indictor. Titrate the solution with EDTA from the burette until the colour
changes from wine- red to steel blue at the end point. Repeat the titration for concordant values. Let the
titre value be V 1ml.


16


Titration-II
SAMPLE HARD WATER Vs Std EDTA Indicator: EBT

S.No. Volume of sample
hard water (ml)
Burette Reading Volume of
EDTA
(V 2) (ml)
Concordant value

Initial

Final




CALCULATION

Calculation of total hardness


Volume of EDTA consumed (V 2) = ------------------------- ml
1ml of EDTA = 20 / V 1 mg of CaCO 3
V 2 ml of EDTA = 20 / V 1 x V 2 mg of CaCO 3

( i.e), If 20ml of sample hard water contains 20 x V 2 mg of CaCO 3 / V 1

Then 1000ml of water sample = 20 x V 2 x 1000 / V 1 x 20 mg of CaCO 3

= 1000 x V 2 / V 1 mg of CaCO3

Total hardness of given water sample = ---------------------ppm









17



DETERMINATION OF TOTAL HARDNESS

Pipette out 20ml of sample hard water into a clean conical flask. Add 5ml of buffer solution and 4 -5
drops of Eriochrome black -T indicator. Titrate the wine - red coloured solution with EDTA from the burette until
the colour steel blue appears at the end point. Repeat the titration for concordant values. Let the titre value be
V 2ml.



DETERMINATION OF PERMANENT HARDNESS

Take 100ml of hard water sample in a 500ml beaker and boil gently for about 1hour. Cool, filter it into a
100ml standard flask and make the volume up to the mark. Take 20ml of this solution and proceed it in the same
way as in titration (I). The volume of EDTA consumed corresponds to the permanent hardness of the water
sample. Let the titre value be V 3ml. Temporary hardness is calculated by subtracting permanent hardness from
total hardness.





















18




DETERMINATION OF PERMANENT HARDNESS
BOILED SAMPLE WATER Vs Std. EDTA Indicator: EBT


S.No.
Volume of boiled
hard water (ml)
Burette Reading (ml) Volume of
EDTA
(ml)

Concordant value

Initial Final



CALCULATION OF PERMANENT HARDNESS


Volume of EDTA consumed V 3 = ---------------------ml

1ml of EDTA = 20 / V 1 mg of CaCO 3

V 3ml of EDTA = 20 / V 1 x V 3 mg of CaCO 3

(i.e) 20 ml of boiled sample hard water = 20 / V 1 x V 3 mg of CaCO 3

Then 1000ml of boiled water sample = 20 / V 1 x V 3 / 20 * 1000mg of CaCO 3

= 1000 x V 3 / V 1 mg of CaCO 3

permanent hardness of boiled water sample = -----------------ppm

Temporary hardness of the given water sample = Total hardness ? Permanent hardness

= ------------------ppm

19







RESULT

(i) Total hardness of the given sample water = -------------- ppm.
(ii) Permanent hardness of the given sample water = --------------- ppm.
(iii) Temporary hardness of the given sample water = ----------------ppm.







VIVA-VOCE

1. Define ? Hard water
2. What is the structure of EDTA?
3. How will you calculate temporary hardness?
4. What is the role of the buffer in EDTA titration?
5. What is the permissible limit of hardness in drinking water?
6. Name the hardness producing ions present in water.
7. Name two salts which are responsible for temporary hardness.
8. Why is CaCO 3 taken as the standard?
9. Write the expansion of EDTA.
10. What is meant by EBT?











20





SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II
Standardisation of
AgNO 3
Estimation of Chloride
Burette solution

AgNO 3 solution

Std. AgNO 3 solution

Pipette solution

20ml std KCl solution

20 ml water sample

Indicator

1ml K 2CrO 4

1ml K 2CrO 4


End point

yellow to reddish brown

yellow to reddish brown

Titration I
Std. AgNO3 Vs KCl Indicator: Potassium Chromate













CALCULATION

Volume of KCl (V 1) = ------- ml

Strength of KCl (N 1) = ------- N

Volume of Silver Nitrate (V 2) = -------- ml

Strength of Siver Nitrate V 1N 1
N 2 =
V 1

= --------------------- N

S.No.
Volume of KCl
(ml)
Burette Reading (ml)
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

21




Expt.No. 3 ESTIMATION OF CHLORIDE CONTENT IN WATER
(ARGENTOMETRIC METHOD)
AIM
To estimate the amount of chloride present in given water sample by Argentometric method (Mohr?s
method). You are provided with standard solution of NaCl of strength --------N and a approximately N/10 solution of
Silver nitrate.

PRINCIPLE
The Chloride ion in the form of NaCl, KCl, CaCl 2, MgCl 2 etc., present in the water sample can be estimated
by Argentometric method or known as Mohr?s method. It is an example for precipitation titration. The reaction
between std. Sodium chloride and Silver nitrate is given below.
AgNO 3 + NaCl ? AgCl ? + NaNO 3
The completion of reaction can be observed by employing potassium chromate as the indicator. The end
point is the colour change from yellow to reddish brown due to the following reaction.
2AgNO 3 + K 2CrO 4 ? Ag 2CrO 4 ? + 2KNO 3
Potassium chromate indicator will not be precipitated as silver chromate until all the chlorides in the solution
have been precipitated as AgCl Since a precipitation reaction takes place in preference, this reaction takes place
only at the end point.

PROCEDURE
TITRATION I: STANDARDISATION OF SILVER NITRATE
Pipette out 20ml of standard sodium or potassium chloride solution into a clean conical flask. Add 1ml of 5%
K 2CrO 4 indicator, as the solution turns yellow in colour. Titrate it against silver nitrate solution taken in the burette.
Observe the nearness of the end point through the formation of coagulated silver chloride precipitate at the bottom
of the flask. Now add the silver nitrate drop by drop until the solution gets a faint reddish brown tinge. Repeat the
titration for concordant value. Let the volume of silver nitrate be V 2ml.





22






TITRATION - II

Std AgNO3 Vs WATER SAMPLE Indicator: Potassium Chromate













CALCULATION

Volume of Silver Nitrate (V 3) = ------------ ml

Strength of Siver Nitrate (N 3) = ------------- N

Volume of Water sample (V 4) = -------------- ml

Strength of Water sample V 3 N 3
(N 4) =
V 4

= ----------------- N

Amount of Chloride ion present in 1000 ml of the water sample = Equivalent mass of HCl X 1000


= N 4 x 35.46 x 1000


= -----------------mg/l







S.No.
Volume of water
sample (ml)
Burette Reading
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

23





TITRATION - II
ESTIMATION OF CHLORIDE ION

Pipette out 40 ml of the given water sample into a clean conical flask.To this sample add 1ml of 5% K 2CrO 4
indicator and titrate it against the standardized silver nitrate solution taken in the burette and continue the titration
until the solution produces a reddish brown colour. Note down the end point and repeat the titration for
concordance. Let the volume be V 3ml.







RESULT

The amount of chloride ion present in the water sample = ----------------- mg/l.




VIVA-VOCE

1. Why is this method known as Argentometric method?
2.
What is the chemical reaction between AgNO 3 and Cl
-
ions present in water?

3.
What is the form of Chloride ion present in water?

4. What is the reaction between AgNO 3 and K 2CrO 4 ?
5. What is the name of the method used in this titration?
6. Name the link solution used in the determination.
7. Name the solution used to standardize AgNO 3.
8. What is the indicator used in the determination?
9. How will you calculate the amount of chloride ion in the given solution?
10. What is the colour change in the titration?




24




SHORT PROCEDURE


CONTENTS

TITRATION I

TITRATION II
Burette solution

Std Sodium Hydroxide

Std Sodium Hydroxide

Pipette solution

20 ml hydrochloric acid 20 ml hydrochloric acid
Additional solution


20 ml distilled water

20 ml distilled water


End point



Sudden increase in pH
pH gradual increase

Equivalent Weight of HCl = 36.5







ROUGH GRAPH FAIR GRAPH











pH
? pH/ ? V





Volume of NaOH
(ml)
Volume of NaOH
(ml)





25



Expt. No. 4 DETERMINATION OF STRENGTH OF HCl by pH METRY

AIM
To determine the strength of given HCl by pH metry. A standard solution of 0.1N NaOH is provided.

PRINCIPLE
The pH of a solution is related to H
+
ion concentration by the following formula.

. pH = -log [ H
+
]

pH of a solution is indirectly related to H
+
ion concentration. When NaOH is added slowly to HCl, H
+
ions
get neutralized by OH
-
ions. The pH increases slowly.

H
+
+ Cl
-
+ Na
+
+ OH
-
? Na
+
+ Cl
-
+H 2O

When all H
+
ions of HCl are neutralized at the end point, addition of NaOH causes high increase in pH
because of the addition of excess OH
-
ions.

MATERIALS REQUIRED
pH meter, Glass electrode, Burette, Pipette, Std.NaOH, approximately N/10 HCl .

PROCEDURE

The burette is washed with distilled water, rinsed with the given std. Sodium hydroxide and filled with the
same solution. Exactly 10ml of the given HCl solution is pipetted out into a clean beaker. It is then diluted to 50ml
with distilled water. A glass electrode is dipped into the solution and its terminals are connected to a pH meter.

26

TITRATION - I
S.No Volume of
NaOH (ml)
pH
1

2

3

4

5

6

7

8

9

10


TITRATION - II



CALCULATION

Volume of NaOH (V 1) = ------------------- ml ( titre value)
Strength of NaOH (N 1) = ------------------- N
Volume of HCl (V 2) = ------------------ml
Strength of HCl (N 2) = ------------------ N
N 2 = V 1 N 1 / V 2
Strength of HCl = -------------------- N
Amount of HCl present in 1000ml of the given solution = Strength x equivalent weight of HCl
= ------------------ X 36.5
= --------------------- g
S.No Volume of
NaOH (ml)
pH
11

12

13

14

15

16

17

18

19

20

S.No
Volume of
NaOH (ml)
pH ?pH ?V ?pH / ?V
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
27



Now NaOH is gradually added from the burette to HCl taken in the beaker. pH of the solution is noted for
each addition of NaOH. This process is continued until 5 readings are taken after the end point.
A fair titration is performed to find the exact end point.





RESULT

(i) Strength of the given HCl solution = ---------------- N
(ii) Amount of HCl present in a litre of the solution = ---------------- g


VIVA-VOCE

1. What is meant by pH?
2. What is the name of the reference electrode used ?
3. Why does pH value increase suddenly at the end point?
4. What is the indicator used in the titration?
5. What is the pH range of human blood?
6. What is the unit of pH?
7. How will you calculate the amount of HCl?
8. How is glass electrode represented?
9. Why is glass electrode known as ion selective electrode?
10. What is the chemical reaction involved in this titration?





28




SHORT PROCEDURE


CONTENTS
TITRATION
Burette solution

Std Sodium Hydroxide

Pipette solution

20 ml mixture of acid (HCl+ CH 3COOH)


Additional solution

20 ml distilled water


End point

Conductivity decreases-slowly increases-Sudden increase



Equivalent Weight of HCl = 36.5


Equivalent Weight of CH 3COOH = 60



MODEL GRAPH


Conductance
Volume of NaOH
Mixture of Acids






29




Expt. No. 5 CONDUCTOMETRIC TITRATION OF MIXTURE
OF ACIDS

AIM
To determine the amount of a strong acid and a weak acid present in the given solution.

PRINCIPLE

Solution of electrolytes conducts electricity due to the presence of ions. Since specific conductance of a
solution is proportional to the concentration of ions in it, conductance of the solution is measured during the titration.

HCl + NaOH ? NaCl + H 2O (I neutralization)

CH 3COOH + NaOH ? CH 3COONa + H 2O (II neutralization)

When a solution of HCl is treated with NaOH the fast moving hydrogen ions are progressively replaced by
slow moving sodium ions. As a result conductance of the solution decreases. This decrease will take place until the
first neutralisation point is reached. Further addition of alkali results in formation of sodium acetate.

Since sodium acetate is stronger than acetic acid conductivity slowly increases until all acetic acid is
completely neutralized.(II Neutralisation) This is due to the presence of fast moving OH
-
ions. Anymore addition of
alkali increases the conductance sharply.

PROCEDURE
The burette is filled with NaOH solution upto zero mark. The given unknown solution (mixture of a weak &
a strong acid) is transferred into a 100ml standard flask and made upto the mark with distilled water. 20ml of the
made up solution is pipetted out into a clean 100ml beaker. The solution is diluted to 20ml using distilled water. A
conductivity cell is dipped into the solution and the terminals are connected to a conductivity meter.
30


TITRATION


CALCULATION OF STRENGTH OF HCl
Volume of NaOH (V 1) = --------------- ml (titre value)
Strength of NaOH (N 1) = ---------------- N
Volume of HCl (V 2) = ------------ ml
Strength of HCl (N 2) = -------------- N

N 2 = V 1 N 1 / V 2
Strength of HCl = ---------------- N
CALCULATION OF STRENGTH OF CH3COOH
Volume of NaOH (V 1) = ------------ ml (titre value)
Strength of NaOH (N 1) = ------------ N
Volume of CH 3COOH (V 2) = ------------ ml
Strength of CH 3COOH (N 2) = ------------ N
N 2 = V 1 N 1 / V 2

Strength of CH 3COOH = ------------ N



S.No

Volume of NaOH
(ml)

Conductance (mho)

14

15

16

17
18
19
20

21
22
23
24
25
26

S.No

Volume of NaOH
(ml)

Conductance (mho)

1
2
3
4
5
6
7
8
9
10
11
12
13
31

The burette solution is added to the unknown solution in the beaker in 0.5 ml increments, the solution is
stirred using a glass rod, and the observed conductance values are read from the meter. The conductance values
show decrease in the initial values, then gradually increases and finally shows a steep increase. The titration hence
shows two end-points (i.e) I neutralization (weak acid) & II neutralization (strong acid).
The accurate end-point is obtained by plotting a graph between observed conductance Vs volume of
NaOH added.

RESULT
The strength of acids present in the given unknown solution are:
a) Strong acid = ---------------- N
b) Weak acid = -----------------N



VIVA-VOCE

1. What is weak acid?
2. How many end points are obtained from the graph? Comment two end points.
3. Why is the conductance increase in the first end point?
4. What mixture of acids used in this titration?
5. Write the neutralization reaction between CH 3COOH and NaOH.
6. What is the solution present in the conductivity cell?
7. What are strong and weak electrolytes?
8. Give an example for strong acid and weak acid.
9. What is the strong electrolyte of weak electrolyte?
10. Give an example for strong base.









32

SHORT PROCEDURE



















ROUGH GRAPH







EMF(mV)






Volume of Potassium dichromate (ml)

FAIR GRAPH









? E / ? V

Volume of Potassium dichromate (ml)




CONTENTS

TITRATION I

TITRATION II
Burette solution

Std Potassium dichromate

Std Potassium dichromate

Pipette solution

10 ml of FAS


10 ml of FAS



Additional
solution

20 ml distilled water+
10 ml of dil H 2SO 4


20 ml distilled water+
10 ml of dil H 2SO 4

End point

Sudden increase in EMF

EMF increases and decreases

Equivalent Weight of Ferrous ion = 55.85

33


Expt. No. 6 ESTIMATION OF FERROUS ION BY POTENTIOMETRIC
TITRATION

AIM
To estimate the amount of ferrous ion present in whole of the given solution potentiometrically. A standard
solution of potassium dichromate of strength -----------N is provided.

PRINCIPLE

Potentiometric titrations depend on measurement of emf between reference electrode and an indicator
electrode. When a solution of ferrous iron is titrated with a solution of potassium dichromate, the following redox
reaction takes place.

6Fe
2+
+ Cr 2O 7
2-
+ 14 H
+
? 6Fe
3+
+ 2Cr
3+
+ 7H 2O

During this titration Fe
2+
is converted in to Fe
3+
, whose concentration increases. At the end point, there
will be a sharp change due to sudden removal of all Fe
2+
ions.
The cell is set up by connecting this redox electrode with a calomel electrode as shown below:

Pt, Fe
2+
, Fe
3+
, II KCl , HgCl 2 (s), Hg

A graph between EMF measured against the volume of potassium dichromate added is drawn and the
end point is noted from the graph.

PROCEDURE

10ml of Ferrous solution is pipetted out into a 100 ml beaker. 10ml of dil.H 2SO 4 and 20ml of distilled water
are added. A platinum electrode and a calomel electrode are dipped into this solution and connected to the
potentiometer. Then 1ml of potassium dichromate is added to the solution and stirred well for 30 seconds. The
EMF is measured and the titration is continued by adding potassium dichromate in 1ml increments till five
measurements after the end point.



34


ROUGH TITRATION



S.No.

Volume of dichromate (ml)

EMF (mV)


1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.





35







A graph is drawn by plotting the emf against the volume of potassium dichromate and the end point range is
fixed.


About 20ml of Ferrous solution is pipetted out and the titration is continued by adding 0.1ml increaments of
potassium dichromate in the end point range. The emf is measured for each 0.1ml after stirring the solution well.


A graph is plotted between emf and the volume of potassium dichromate and also a first derivative graph is
plotted ( ? E/ ? V against vol. of K 2Cr 2O 7). The strength of Ferrous solution and the amount of Ferrous ion present are
calculated from the end point.



























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?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





3


PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)
1. Fundamentals
To provide students with a solid foundation in Mathematics, Science and fundamentals of engineering,
enabling them to apply, to find solutions for engineering problems and use this knowledge to acquire higher
education
2. Core Competence
To train the students in chemistry practicals so that they apply their knowledge and training to compare,
and to analyze various engineering industrial problems to find solutions
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice this enables
them to find solutions for the real time problems in industry, and to design products
4. Professionalism
To inculcate professional and effective communication skills, leadership qualities and team spirit in the
students to make them multi-faceted personalities and develop their ability to relate engineering issues to
broader social context
5. Lifelong Learning/Ethics
To demonstrate and practice ethical and professional responsibilities in the industry and society in the
large, through commitment and lifelong learning needed for successful professional career






4


PROGRAMME OUTCOMES (POs)
To demonstrate and apply knowledge of Mathematics, Science and engineering fundamentals in the following
experiments.
1 .To estimate HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. To determine total, temporary & permanent hardness of water by EDTA method.
3. To determine DO content of water sample by Winkler?s method.
4. To determine chloride content of water sample by Argentometric method.
5. To estimate copper content of the given solution by Iodometry.
6. To determine strength of given hydrochloric acid using pH meter.
7. To determine strength of acids in a mixture of acids using conductivity meter.
8. To determine iron content of the given solution using potentiometer.
9. To estimate iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. To estimate sodium and potassium present in water using flame photometer.
11. To determine molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. To determine Pseudo first order kinetics ? ester hydrolysis.
13. To determine Corrosion experiment ? weight loss method.
14. To estimate CMC.
15. To estimate Phase change in a solid.
16. To determine strength of strong acid vs strong base using conductivity meter.











5

BS8161 - CHEMISTRY LABORATORY
SYLLABUS


? To make the student to acquire practical skills in the determination of water quality
parameters through volumetric and instrumental analysis.

? ???? ??? ???? ?? ???? ? ? ?To acquaint the students with the determination of molecular weight of a polymer by
viscometery.

LIST OF EXPERIMENTS:
1. Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. Determination of total, temporary & permanent hardness of water by EDTA method.
3. Determination of DO content of water sample by Winkler?s method.
4. Determination of chloride content of water sample by Argentometric method.
5. Estimation of copper content of the given solution by Iodometry.
6. Determination of strength of given hydrochloric acid using pH meter.
7. Determination of strength of acids in a mixture of acids using conductivity meter.
8. Estimation of iron content of the given solution using potentiometer.
9. Estimation of iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. Estimation of sodium and potassium present in water using flame photometer.
11. Determination of molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. Pseudo first order kinetics ? ester hydrolysis.
13. Corrosion experiment ? weight loss method.
14. Determination of CMC.
15. Phase change in a solid.
16. Conductometric titration of strong acid vs strong base.




? The students will be outfitted with hands-on knowledge in the quantitative chemical
analysis of water quality related parameters.
COURSE OBJECTIVES
COURSE OUTCOMES
6


INDEX [ SEMESTER ? I ]


S.No.



Date


Experiment

Date of
submission



Mark


Signature

1.

Estimation of HCl using Na 2CO 3 as
primary standard and Determination of
alkalinity in water sample.



2.


Determination of total, temporary &
permanent hardness of water by EDTA
method.



3.


Determination of chloride content of water
sample by argentometric method.



4.


Determination of strength of given
hydrochloric acid using pH meter.



5.


Determination of strength of acids in a
mixture of acids using conductivity meter.



6.


Estimation of iron content of the given
solution using potentiometer.



7.





Conductometric titration of strong acid Vs
strong base.



8.



Estimation of copper content of the given
solution by Iodometry


9.
Estimation of sodium and potassium
present in water using flame photometer




7




CONTENTS


S.No.


NAME OF EXPERIMENT

PAGE
No.
SEMESTER - I
1.
Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in
water sample.
09
2. Determination of total, temporary & permanent hardness of water by EDTA method. 15
3. Determination of chloride content of water sample by Argentometric method. 21
4. Determination of strength of given hydrochloric acid using pH meter. 25
5. Determination of strength of acids in a mixture of acids using conductivity meter. 29
6. Estimation of iron content of the given solution using potentiometer. 33
7. Conductometric titration of strong acid Vs strong base.

39


42

8


Estimation of copper content of the given solution by Iodometry 43
9 Estimation of sodium and potassium present in water using flame photometer 47






8



SHORT PROCEDURE:

CONTENTS
TITRATION
Estimation of alkalinity in water sample
(Std HCl Vs water sample)

Burette solution

Std. HCl


Pipette solution

Water sample


Indicator


(i) Phenolphthalein
(ii) Methyl orange


End point

(i) Disappearance of pink colour
(ii) Appearance of reddish orange colour






Relationship
between P &M
Nature of alkalinity
Amount of individual
alkalinities
OH
-
HCO 3
-


CO 3
2-

P = M

only OH
-

P or M

?
0.0

0.0


2P = M

only CO 3
2-


2P or M


0.0


0.0


?

P =0, M?0

only HCO 3
-



M



0.0



?

0.0


2P > M


OH
-
&CO 3
2-


OH
-
= 2P-M
CO 3
2-
= 2(M-P)


?

0.0

?

P < ? M




HCO 3
-
&CO 3
2-


HCO 3
-
= M-2P
CO 3
2-
= 2P

0.0 ? ?




9





Expt. No. 1 DETERMINATION OF ALKALINITY IN WATER
AIM
To determine the type and amounts of alkalinity in the given water sample. A standard solution of Na 2CO 3
of strength ____N is given.

PRINCIPLE
Alkalinity in water is due to the presence of soluble hydroxides, bicarbonates and carbonates.
Determination of various types and amounts of alkalinity is easily carried out by titration with standard HCl
employing the indicators phenolphthalein and methyl orange independently or in succession.

The following reactions occur when different types of alkalinity are neutralized with acid.

OH
?
+ H
+
? H 2O completed at pH 8.2-9.0 ----- (1)

CO 3
2 ?
+ H
+
? HCO 3
?
----- (2)

HCO 3
?
+ H
+
? (H 2CO 3) ? H 2O + CO 2, completed at pH 4.2-5.5 ----- (3)

Neutralisation (1) & (2) will be notified by phenolphthalein end-point while all the three will be

accounted by
methyl orange end-point. Bicarbonate in eqn. (3) may be due to the existence of soluble free bicarbonate salts and
bicarbonates resulting from half neutralization of soluble carbonates (eqn. (2))

Various steps to be followed

a) A known volume of water sample is titrated against std. HCl using first phenolphthalein indicator till
end-point (P) and the titration is continued without break using methyl orange indicator till the end-
point (M).



10


Titration

Estimation of Alkalinity in water sample

Standard HCl Vs Water sample Indicator: 1. Phenolphthalein
2. Methyl Orange


S.No.
Volume
of water
sample (ml)
Burette Reading
Concordant value

Initial Phenolphthalein End
Point (P)
Methyl Orange End
Point (M)

1

2






CALCULATION

Hydroxide ion alkalinity
Volume of HCl (2P-M) = ???????ml

Strength of HCl = ???????? N

Volume of water sample = ???????...ml

Strength of water sample = Volume of HCl (2P-M) x Strength of HCl
Volume of water sample

=

? Hydroxide ion alkalinity in terms of
CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ??????.mg/l







11




b) From the magnitudes of the P & M, the nature of alkalinity can be arrived as follows:

(i) P = M => Presence of only OH
-

(ii) 2P = M => Presence of only CO 3
2-

(iii) P =0, M=0 => Presence of only HCO 3
-
(iv) 2P > M => Presence of OH
-
& CO 3
2-
(v) 2P < M => Presence of HCO 3
-
& CO 3
2-

(Mixture of OH
-
& HCO3
-
is not listed since they do not exist together and are considered equivalent to CO 3
2-
).

PROCEDURE
TITRATION
ESTIMATION OF ALKALINITY IN WATER SAMPLE

Exactly 20 ml of water sample is pipetted out into a clean conical flask. Few drops of phenolphthalein
indicator are added and titrated against a standardized HCl taken in the burette. The end point is the
disappearance of pink colour, which is noted as P. Few drops of methyl orange indicator is added to the same
solution. The solution turns to yellow. The titration is continued further by adding same HCl without break till the
end point is reached. The end point is the colour change from yellow to reddish orange.

The experiment is repeated to get concordant values. From the magnitudes of P & M values, the type of
alkalinity present in the water sample is inferred and the individual amounts are calculated and reported.










12


Carbonate ion alkalinity

Volume of HCl 2 (M ? P) = ??? ????????ml

Strength of HCl = ??.?????..???...N

Volume of water sample =........................................ml

Strength of water sample = Volume of HCl 2 (M ? P) x Strength of HCl
Volume of water sample

= ???????????.. N




? Carbonate ion alkalinity
in terms of CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ???????????mg/l

















13





RESULT

1) The type of alkalinity present in the water sample = -------------------------ions.

2) The individual amounts of alkalinity present in the water sample:
Hydroxide ion alkalinity

= ----------------- ppm
Carbonate ion alkalinity = ------------------ ppm
Bicarbonate ion alkalinity = ----------------- ppm





VIVA-VOCE


1. What is meant by alkalinity?
2. What are the ions responsible for alkalinity?
3. Why OH
-
and HCO 3
?
ions cannot exist together in water?
4. What are the ions responsible for alkalinity when 2P > M?
5. What is the pH range for both in acidic and basic solutions?
6. What is the colour of phenolphthalein in an acid and in an alkaline solution?
7. What is the purpose of using two indicators in same titration?
8. What are the possible combinations of ions for alkalinity?
9. How is the amount of alkalinity expressed?
10. What are the types of indicator used in this experiment?







14

SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II TITRATION III
Standardisation of
EDTA
(EDTA Vs Std
Hard water)
Determination of
total hardness
(Std EDTA Vs Hard
water sample)
Determination of
permanent hardness
(Std EDTA Vs Boiled
Hard water sample)

Burette solution

EDTA solution

EDTA solution

EDTA solution

Pipette solution

20ml Std. hard water

20 ml hard water sample

20ml boiled hard water sample

Indicator

2 drops of EBT

2 drops of EBT

2 drops of EBT

Additional soln.


Ammoniacal Buffer
solution (5ml)

Ammoniacal Buffer solution
(5ml)

Ammoniacal Buffer solution
(5ml)
End point Wine - red to Steel blue Wine - red to steel blue Wine - red to Steel blue




STANDARDISATION OF EDTA
Titration - I
Std. HARD WATER Vs EDTA Indicator: EBT

S. No.
Volume of std hard
water (ml)
Burette Reading Volume of
EDTA
(V 1) (ml)
Concordant value

Initial

Final



Volume of std .hard water taken = 20 ml
Volume of EDTA consumed (V 1) = --------------- ml
1 ml of std.hard water = 1mg of CaCO 3
20 ml of std hard water = 20 mg of CaCO 3

V 1 ml of EDTA solution containing 20 mg of CaCO 3
1 ml of EDTA solution = 20 / V 1 mg of CaCO 3
= -----------------------mg of CaCO 3


15

Expt. No. 2 DETERMINATION OF TOTAL, TEMPORARY AND
PERMANENT HARDNESS OF WATER

AIM
To estimate the amount of total, temporary & permanent hardness in the given sample of water.

PRINCIPLE
The estimation is based on the complexometric titration.

(i) Total hardness of water is estimated by titrating against EDTA using EBT indicator.
EBT+M ?[EBT-M] (unstable complex)
(EBT-M) (Unstable complex) +EDTA ? [EDTA-M] (stable complex) +EBT
EBT indicator forms wine- red colored complex with metal ions present in water. On addition of EDTA
metal ions preferably forms complexes with EDTA and steel blue EBT indicator is set free. Therefore
change of colour from wine- red to steel blue denotes the end point.

(ii) Temporary hardness is removed by boiling the water.
Ca (HCO 3) 2 ? CaCO 3 +CO 2 ?+H 2O
Mg (HCO 3) 2 ? Mg(OH) 2 +2CO 2 ?
The precipitate is filtered and the remaining permanent hardness is estimated using EDTA.

PROCEDURE

TITRATION ? I
STANDARDISATION OF EDTA

Pipette out 20ml of standard hard water into a 250ml conical flask. Add 5ml of buffer solution and 3
drops of eriochrome black T indictor. Titrate the solution with EDTA from the burette until the colour
changes from wine- red to steel blue at the end point. Repeat the titration for concordant values. Let the
titre value be V 1ml.


16


Titration-II
SAMPLE HARD WATER Vs Std EDTA Indicator: EBT

S.No. Volume of sample
hard water (ml)
Burette Reading Volume of
EDTA
(V 2) (ml)
Concordant value

Initial

Final




CALCULATION

Calculation of total hardness


Volume of EDTA consumed (V 2) = ------------------------- ml
1ml of EDTA = 20 / V 1 mg of CaCO 3
V 2 ml of EDTA = 20 / V 1 x V 2 mg of CaCO 3

( i.e), If 20ml of sample hard water contains 20 x V 2 mg of CaCO 3 / V 1

Then 1000ml of water sample = 20 x V 2 x 1000 / V 1 x 20 mg of CaCO 3

= 1000 x V 2 / V 1 mg of CaCO3

Total hardness of given water sample = ---------------------ppm









17



DETERMINATION OF TOTAL HARDNESS

Pipette out 20ml of sample hard water into a clean conical flask. Add 5ml of buffer solution and 4 -5
drops of Eriochrome black -T indicator. Titrate the wine - red coloured solution with EDTA from the burette until
the colour steel blue appears at the end point. Repeat the titration for concordant values. Let the titre value be
V 2ml.



DETERMINATION OF PERMANENT HARDNESS

Take 100ml of hard water sample in a 500ml beaker and boil gently for about 1hour. Cool, filter it into a
100ml standard flask and make the volume up to the mark. Take 20ml of this solution and proceed it in the same
way as in titration (I). The volume of EDTA consumed corresponds to the permanent hardness of the water
sample. Let the titre value be V 3ml. Temporary hardness is calculated by subtracting permanent hardness from
total hardness.





















18




DETERMINATION OF PERMANENT HARDNESS
BOILED SAMPLE WATER Vs Std. EDTA Indicator: EBT


S.No.
Volume of boiled
hard water (ml)
Burette Reading (ml) Volume of
EDTA
(ml)

Concordant value

Initial Final



CALCULATION OF PERMANENT HARDNESS


Volume of EDTA consumed V 3 = ---------------------ml

1ml of EDTA = 20 / V 1 mg of CaCO 3

V 3ml of EDTA = 20 / V 1 x V 3 mg of CaCO 3

(i.e) 20 ml of boiled sample hard water = 20 / V 1 x V 3 mg of CaCO 3

Then 1000ml of boiled water sample = 20 / V 1 x V 3 / 20 * 1000mg of CaCO 3

= 1000 x V 3 / V 1 mg of CaCO 3

permanent hardness of boiled water sample = -----------------ppm

Temporary hardness of the given water sample = Total hardness ? Permanent hardness

= ------------------ppm

19







RESULT

(i) Total hardness of the given sample water = -------------- ppm.
(ii) Permanent hardness of the given sample water = --------------- ppm.
(iii) Temporary hardness of the given sample water = ----------------ppm.







VIVA-VOCE

1. Define ? Hard water
2. What is the structure of EDTA?
3. How will you calculate temporary hardness?
4. What is the role of the buffer in EDTA titration?
5. What is the permissible limit of hardness in drinking water?
6. Name the hardness producing ions present in water.
7. Name two salts which are responsible for temporary hardness.
8. Why is CaCO 3 taken as the standard?
9. Write the expansion of EDTA.
10. What is meant by EBT?











20





SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II
Standardisation of
AgNO 3
Estimation of Chloride
Burette solution

AgNO 3 solution

Std. AgNO 3 solution

Pipette solution

20ml std KCl solution

20 ml water sample

Indicator

1ml K 2CrO 4

1ml K 2CrO 4


End point

yellow to reddish brown

yellow to reddish brown

Titration I
Std. AgNO3 Vs KCl Indicator: Potassium Chromate













CALCULATION

Volume of KCl (V 1) = ------- ml

Strength of KCl (N 1) = ------- N

Volume of Silver Nitrate (V 2) = -------- ml

Strength of Siver Nitrate V 1N 1
N 2 =
V 1

= --------------------- N

S.No.
Volume of KCl
(ml)
Burette Reading (ml)
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

21




Expt.No. 3 ESTIMATION OF CHLORIDE CONTENT IN WATER
(ARGENTOMETRIC METHOD)
AIM
To estimate the amount of chloride present in given water sample by Argentometric method (Mohr?s
method). You are provided with standard solution of NaCl of strength --------N and a approximately N/10 solution of
Silver nitrate.

PRINCIPLE
The Chloride ion in the form of NaCl, KCl, CaCl 2, MgCl 2 etc., present in the water sample can be estimated
by Argentometric method or known as Mohr?s method. It is an example for precipitation titration. The reaction
between std. Sodium chloride and Silver nitrate is given below.
AgNO 3 + NaCl ? AgCl ? + NaNO 3
The completion of reaction can be observed by employing potassium chromate as the indicator. The end
point is the colour change from yellow to reddish brown due to the following reaction.
2AgNO 3 + K 2CrO 4 ? Ag 2CrO 4 ? + 2KNO 3
Potassium chromate indicator will not be precipitated as silver chromate until all the chlorides in the solution
have been precipitated as AgCl Since a precipitation reaction takes place in preference, this reaction takes place
only at the end point.

PROCEDURE
TITRATION I: STANDARDISATION OF SILVER NITRATE
Pipette out 20ml of standard sodium or potassium chloride solution into a clean conical flask. Add 1ml of 5%
K 2CrO 4 indicator, as the solution turns yellow in colour. Titrate it against silver nitrate solution taken in the burette.
Observe the nearness of the end point through the formation of coagulated silver chloride precipitate at the bottom
of the flask. Now add the silver nitrate drop by drop until the solution gets a faint reddish brown tinge. Repeat the
titration for concordant value. Let the volume of silver nitrate be V 2ml.





22






TITRATION - II

Std AgNO3 Vs WATER SAMPLE Indicator: Potassium Chromate













CALCULATION

Volume of Silver Nitrate (V 3) = ------------ ml

Strength of Siver Nitrate (N 3) = ------------- N

Volume of Water sample (V 4) = -------------- ml

Strength of Water sample V 3 N 3
(N 4) =
V 4

= ----------------- N

Amount of Chloride ion present in 1000 ml of the water sample = Equivalent mass of HCl X 1000


= N 4 x 35.46 x 1000


= -----------------mg/l







S.No.
Volume of water
sample (ml)
Burette Reading
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

23





TITRATION - II
ESTIMATION OF CHLORIDE ION

Pipette out 40 ml of the given water sample into a clean conical flask.To this sample add 1ml of 5% K 2CrO 4
indicator and titrate it against the standardized silver nitrate solution taken in the burette and continue the titration
until the solution produces a reddish brown colour. Note down the end point and repeat the titration for
concordance. Let the volume be V 3ml.







RESULT

The amount of chloride ion present in the water sample = ----------------- mg/l.




VIVA-VOCE

1. Why is this method known as Argentometric method?
2.
What is the chemical reaction between AgNO 3 and Cl
-
ions present in water?

3.
What is the form of Chloride ion present in water?

4. What is the reaction between AgNO 3 and K 2CrO 4 ?
5. What is the name of the method used in this titration?
6. Name the link solution used in the determination.
7. Name the solution used to standardize AgNO 3.
8. What is the indicator used in the determination?
9. How will you calculate the amount of chloride ion in the given solution?
10. What is the colour change in the titration?




24




SHORT PROCEDURE


CONTENTS

TITRATION I

TITRATION II
Burette solution

Std Sodium Hydroxide

Std Sodium Hydroxide

Pipette solution

20 ml hydrochloric acid 20 ml hydrochloric acid
Additional solution


20 ml distilled water

20 ml distilled water


End point



Sudden increase in pH
pH gradual increase

Equivalent Weight of HCl = 36.5







ROUGH GRAPH FAIR GRAPH











pH
? pH/ ? V





Volume of NaOH
(ml)
Volume of NaOH
(ml)





25



Expt. No. 4 DETERMINATION OF STRENGTH OF HCl by pH METRY

AIM
To determine the strength of given HCl by pH metry. A standard solution of 0.1N NaOH is provided.

PRINCIPLE
The pH of a solution is related to H
+
ion concentration by the following formula.

. pH = -log [ H
+
]

pH of a solution is indirectly related to H
+
ion concentration. When NaOH is added slowly to HCl, H
+
ions
get neutralized by OH
-
ions. The pH increases slowly.

H
+
+ Cl
-
+ Na
+
+ OH
-
? Na
+
+ Cl
-
+H 2O

When all H
+
ions of HCl are neutralized at the end point, addition of NaOH causes high increase in pH
because of the addition of excess OH
-
ions.

MATERIALS REQUIRED
pH meter, Glass electrode, Burette, Pipette, Std.NaOH, approximately N/10 HCl .

PROCEDURE

The burette is washed with distilled water, rinsed with the given std. Sodium hydroxide and filled with the
same solution. Exactly 10ml of the given HCl solution is pipetted out into a clean beaker. It is then diluted to 50ml
with distilled water. A glass electrode is dipped into the solution and its terminals are connected to a pH meter.

26

TITRATION - I
S.No Volume of
NaOH (ml)
pH
1

2

3

4

5

6

7

8

9

10


TITRATION - II



CALCULATION

Volume of NaOH (V 1) = ------------------- ml ( titre value)
Strength of NaOH (N 1) = ------------------- N
Volume of HCl (V 2) = ------------------ml
Strength of HCl (N 2) = ------------------ N
N 2 = V 1 N 1 / V 2
Strength of HCl = -------------------- N
Amount of HCl present in 1000ml of the given solution = Strength x equivalent weight of HCl
= ------------------ X 36.5
= --------------------- g
S.No Volume of
NaOH (ml)
pH
11

12

13

14

15

16

17

18

19

20

S.No
Volume of
NaOH (ml)
pH ?pH ?V ?pH / ?V
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
27



Now NaOH is gradually added from the burette to HCl taken in the beaker. pH of the solution is noted for
each addition of NaOH. This process is continued until 5 readings are taken after the end point.
A fair titration is performed to find the exact end point.





RESULT

(i) Strength of the given HCl solution = ---------------- N
(ii) Amount of HCl present in a litre of the solution = ---------------- g


VIVA-VOCE

1. What is meant by pH?
2. What is the name of the reference electrode used ?
3. Why does pH value increase suddenly at the end point?
4. What is the indicator used in the titration?
5. What is the pH range of human blood?
6. What is the unit of pH?
7. How will you calculate the amount of HCl?
8. How is glass electrode represented?
9. Why is glass electrode known as ion selective electrode?
10. What is the chemical reaction involved in this titration?





28




SHORT PROCEDURE


CONTENTS
TITRATION
Burette solution

Std Sodium Hydroxide

Pipette solution

20 ml mixture of acid (HCl+ CH 3COOH)


Additional solution

20 ml distilled water


End point

Conductivity decreases-slowly increases-Sudden increase



Equivalent Weight of HCl = 36.5


Equivalent Weight of CH 3COOH = 60



MODEL GRAPH


Conductance
Volume of NaOH
Mixture of Acids






29




Expt. No. 5 CONDUCTOMETRIC TITRATION OF MIXTURE
OF ACIDS

AIM
To determine the amount of a strong acid and a weak acid present in the given solution.

PRINCIPLE

Solution of electrolytes conducts electricity due to the presence of ions. Since specific conductance of a
solution is proportional to the concentration of ions in it, conductance of the solution is measured during the titration.

HCl + NaOH ? NaCl + H 2O (I neutralization)

CH 3COOH + NaOH ? CH 3COONa + H 2O (II neutralization)

When a solution of HCl is treated with NaOH the fast moving hydrogen ions are progressively replaced by
slow moving sodium ions. As a result conductance of the solution decreases. This decrease will take place until the
first neutralisation point is reached. Further addition of alkali results in formation of sodium acetate.

Since sodium acetate is stronger than acetic acid conductivity slowly increases until all acetic acid is
completely neutralized.(II Neutralisation) This is due to the presence of fast moving OH
-
ions. Anymore addition of
alkali increases the conductance sharply.

PROCEDURE
The burette is filled with NaOH solution upto zero mark. The given unknown solution (mixture of a weak &
a strong acid) is transferred into a 100ml standard flask and made upto the mark with distilled water. 20ml of the
made up solution is pipetted out into a clean 100ml beaker. The solution is diluted to 20ml using distilled water. A
conductivity cell is dipped into the solution and the terminals are connected to a conductivity meter.
30


TITRATION


CALCULATION OF STRENGTH OF HCl
Volume of NaOH (V 1) = --------------- ml (titre value)
Strength of NaOH (N 1) = ---------------- N
Volume of HCl (V 2) = ------------ ml
Strength of HCl (N 2) = -------------- N

N 2 = V 1 N 1 / V 2
Strength of HCl = ---------------- N
CALCULATION OF STRENGTH OF CH3COOH
Volume of NaOH (V 1) = ------------ ml (titre value)
Strength of NaOH (N 1) = ------------ N
Volume of CH 3COOH (V 2) = ------------ ml
Strength of CH 3COOH (N 2) = ------------ N
N 2 = V 1 N 1 / V 2

Strength of CH 3COOH = ------------ N



S.No

Volume of NaOH
(ml)

Conductance (mho)

14

15

16

17
18
19
20

21
22
23
24
25
26

S.No

Volume of NaOH
(ml)

Conductance (mho)

1
2
3
4
5
6
7
8
9
10
11
12
13
31

The burette solution is added to the unknown solution in the beaker in 0.5 ml increments, the solution is
stirred using a glass rod, and the observed conductance values are read from the meter. The conductance values
show decrease in the initial values, then gradually increases and finally shows a steep increase. The titration hence
shows two end-points (i.e) I neutralization (weak acid) & II neutralization (strong acid).
The accurate end-point is obtained by plotting a graph between observed conductance Vs volume of
NaOH added.

RESULT
The strength of acids present in the given unknown solution are:
a) Strong acid = ---------------- N
b) Weak acid = -----------------N



VIVA-VOCE

1. What is weak acid?
2. How many end points are obtained from the graph? Comment two end points.
3. Why is the conductance increase in the first end point?
4. What mixture of acids used in this titration?
5. Write the neutralization reaction between CH 3COOH and NaOH.
6. What is the solution present in the conductivity cell?
7. What are strong and weak electrolytes?
8. Give an example for strong acid and weak acid.
9. What is the strong electrolyte of weak electrolyte?
10. Give an example for strong base.









32

SHORT PROCEDURE



















ROUGH GRAPH







EMF(mV)






Volume of Potassium dichromate (ml)

FAIR GRAPH









? E / ? V

Volume of Potassium dichromate (ml)




CONTENTS

TITRATION I

TITRATION II
Burette solution

Std Potassium dichromate

Std Potassium dichromate

Pipette solution

10 ml of FAS


10 ml of FAS



Additional
solution

20 ml distilled water+
10 ml of dil H 2SO 4


20 ml distilled water+
10 ml of dil H 2SO 4

End point

Sudden increase in EMF

EMF increases and decreases

Equivalent Weight of Ferrous ion = 55.85

33


Expt. No. 6 ESTIMATION OF FERROUS ION BY POTENTIOMETRIC
TITRATION

AIM
To estimate the amount of ferrous ion present in whole of the given solution potentiometrically. A standard
solution of potassium dichromate of strength -----------N is provided.

PRINCIPLE

Potentiometric titrations depend on measurement of emf between reference electrode and an indicator
electrode. When a solution of ferrous iron is titrated with a solution of potassium dichromate, the following redox
reaction takes place.

6Fe
2+
+ Cr 2O 7
2-
+ 14 H
+
? 6Fe
3+
+ 2Cr
3+
+ 7H 2O

During this titration Fe
2+
is converted in to Fe
3+
, whose concentration increases. At the end point, there
will be a sharp change due to sudden removal of all Fe
2+
ions.
The cell is set up by connecting this redox electrode with a calomel electrode as shown below:

Pt, Fe
2+
, Fe
3+
, II KCl , HgCl 2 (s), Hg

A graph between EMF measured against the volume of potassium dichromate added is drawn and the
end point is noted from the graph.

PROCEDURE

10ml of Ferrous solution is pipetted out into a 100 ml beaker. 10ml of dil.H 2SO 4 and 20ml of distilled water
are added. A platinum electrode and a calomel electrode are dipped into this solution and connected to the
potentiometer. Then 1ml of potassium dichromate is added to the solution and stirred well for 30 seconds. The
EMF is measured and the titration is continued by adding potassium dichromate in 1ml increments till five
measurements after the end point.



34


ROUGH TITRATION



S.No.

Volume of dichromate (ml)

EMF (mV)


1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.





35







A graph is drawn by plotting the emf against the volume of potassium dichromate and the end point range is
fixed.


About 20ml of Ferrous solution is pipetted out and the titration is continued by adding 0.1ml increaments of
potassium dichromate in the end point range. The emf is measured for each 0.1ml after stirring the solution well.


A graph is plotted between emf and the volume of potassium dichromate and also a first derivative graph is
plotted ( ? E/ ? V against vol. of K 2Cr 2O 7). The strength of Ferrous solution and the amount of Ferrous ion present are
calculated from the end point.



























36

FAIR TITRATION

S.No Volume of
Dichromate (ml)
Emf (mV) ?E ?V ?E/?V






















CALCULATION

Volume of Potassim dichromate (V 1) = -------------- ml
Normality of Potassium dichromate (N 1) = --------------- N
Volume of Ferrous sulphate (V 2) = --------------- ml
Normality of Ferrous sulphate (N 2) = --------------- N
Amount of Ferrous ion present in 1000ml of the solution = Normality X Equivalent weight of ferrous ion
= --------------- X 55.85 g

The amount of Ferrous ion present in the given solution = ----------------- g






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?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





3


PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)
1. Fundamentals
To provide students with a solid foundation in Mathematics, Science and fundamentals of engineering,
enabling them to apply, to find solutions for engineering problems and use this knowledge to acquire higher
education
2. Core Competence
To train the students in chemistry practicals so that they apply their knowledge and training to compare,
and to analyze various engineering industrial problems to find solutions
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice this enables
them to find solutions for the real time problems in industry, and to design products
4. Professionalism
To inculcate professional and effective communication skills, leadership qualities and team spirit in the
students to make them multi-faceted personalities and develop their ability to relate engineering issues to
broader social context
5. Lifelong Learning/Ethics
To demonstrate and practice ethical and professional responsibilities in the industry and society in the
large, through commitment and lifelong learning needed for successful professional career






4


PROGRAMME OUTCOMES (POs)
To demonstrate and apply knowledge of Mathematics, Science and engineering fundamentals in the following
experiments.
1 .To estimate HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. To determine total, temporary & permanent hardness of water by EDTA method.
3. To determine DO content of water sample by Winkler?s method.
4. To determine chloride content of water sample by Argentometric method.
5. To estimate copper content of the given solution by Iodometry.
6. To determine strength of given hydrochloric acid using pH meter.
7. To determine strength of acids in a mixture of acids using conductivity meter.
8. To determine iron content of the given solution using potentiometer.
9. To estimate iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. To estimate sodium and potassium present in water using flame photometer.
11. To determine molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. To determine Pseudo first order kinetics ? ester hydrolysis.
13. To determine Corrosion experiment ? weight loss method.
14. To estimate CMC.
15. To estimate Phase change in a solid.
16. To determine strength of strong acid vs strong base using conductivity meter.











5

BS8161 - CHEMISTRY LABORATORY
SYLLABUS


? To make the student to acquire practical skills in the determination of water quality
parameters through volumetric and instrumental analysis.

? ???? ??? ???? ?? ???? ? ? ?To acquaint the students with the determination of molecular weight of a polymer by
viscometery.

LIST OF EXPERIMENTS:
1. Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. Determination of total, temporary & permanent hardness of water by EDTA method.
3. Determination of DO content of water sample by Winkler?s method.
4. Determination of chloride content of water sample by Argentometric method.
5. Estimation of copper content of the given solution by Iodometry.
6. Determination of strength of given hydrochloric acid using pH meter.
7. Determination of strength of acids in a mixture of acids using conductivity meter.
8. Estimation of iron content of the given solution using potentiometer.
9. Estimation of iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. Estimation of sodium and potassium present in water using flame photometer.
11. Determination of molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. Pseudo first order kinetics ? ester hydrolysis.
13. Corrosion experiment ? weight loss method.
14. Determination of CMC.
15. Phase change in a solid.
16. Conductometric titration of strong acid vs strong base.




? The students will be outfitted with hands-on knowledge in the quantitative chemical
analysis of water quality related parameters.
COURSE OBJECTIVES
COURSE OUTCOMES
6


INDEX [ SEMESTER ? I ]


S.No.



Date


Experiment

Date of
submission



Mark


Signature

1.

Estimation of HCl using Na 2CO 3 as
primary standard and Determination of
alkalinity in water sample.



2.


Determination of total, temporary &
permanent hardness of water by EDTA
method.



3.


Determination of chloride content of water
sample by argentometric method.



4.


Determination of strength of given
hydrochloric acid using pH meter.



5.


Determination of strength of acids in a
mixture of acids using conductivity meter.



6.


Estimation of iron content of the given
solution using potentiometer.



7.





Conductometric titration of strong acid Vs
strong base.



8.



Estimation of copper content of the given
solution by Iodometry


9.
Estimation of sodium and potassium
present in water using flame photometer




7




CONTENTS


S.No.


NAME OF EXPERIMENT

PAGE
No.
SEMESTER - I
1.
Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in
water sample.
09
2. Determination of total, temporary & permanent hardness of water by EDTA method. 15
3. Determination of chloride content of water sample by Argentometric method. 21
4. Determination of strength of given hydrochloric acid using pH meter. 25
5. Determination of strength of acids in a mixture of acids using conductivity meter. 29
6. Estimation of iron content of the given solution using potentiometer. 33
7. Conductometric titration of strong acid Vs strong base.

39


42

8


Estimation of copper content of the given solution by Iodometry 43
9 Estimation of sodium and potassium present in water using flame photometer 47






8



SHORT PROCEDURE:

CONTENTS
TITRATION
Estimation of alkalinity in water sample
(Std HCl Vs water sample)

Burette solution

Std. HCl


Pipette solution

Water sample


Indicator


(i) Phenolphthalein
(ii) Methyl orange


End point

(i) Disappearance of pink colour
(ii) Appearance of reddish orange colour






Relationship
between P &M
Nature of alkalinity
Amount of individual
alkalinities
OH
-
HCO 3
-


CO 3
2-

P = M

only OH
-

P or M

?
0.0

0.0


2P = M

only CO 3
2-


2P or M


0.0


0.0


?

P =0, M?0

only HCO 3
-



M



0.0



?

0.0


2P > M


OH
-
&CO 3
2-


OH
-
= 2P-M
CO 3
2-
= 2(M-P)


?

0.0

?

P < ? M




HCO 3
-
&CO 3
2-


HCO 3
-
= M-2P
CO 3
2-
= 2P

0.0 ? ?




9





Expt. No. 1 DETERMINATION OF ALKALINITY IN WATER
AIM
To determine the type and amounts of alkalinity in the given water sample. A standard solution of Na 2CO 3
of strength ____N is given.

PRINCIPLE
Alkalinity in water is due to the presence of soluble hydroxides, bicarbonates and carbonates.
Determination of various types and amounts of alkalinity is easily carried out by titration with standard HCl
employing the indicators phenolphthalein and methyl orange independently or in succession.

The following reactions occur when different types of alkalinity are neutralized with acid.

OH
?
+ H
+
? H 2O completed at pH 8.2-9.0 ----- (1)

CO 3
2 ?
+ H
+
? HCO 3
?
----- (2)

HCO 3
?
+ H
+
? (H 2CO 3) ? H 2O + CO 2, completed at pH 4.2-5.5 ----- (3)

Neutralisation (1) & (2) will be notified by phenolphthalein end-point while all the three will be

accounted by
methyl orange end-point. Bicarbonate in eqn. (3) may be due to the existence of soluble free bicarbonate salts and
bicarbonates resulting from half neutralization of soluble carbonates (eqn. (2))

Various steps to be followed

a) A known volume of water sample is titrated against std. HCl using first phenolphthalein indicator till
end-point (P) and the titration is continued without break using methyl orange indicator till the end-
point (M).



10


Titration

Estimation of Alkalinity in water sample

Standard HCl Vs Water sample Indicator: 1. Phenolphthalein
2. Methyl Orange


S.No.
Volume
of water
sample (ml)
Burette Reading
Concordant value

Initial Phenolphthalein End
Point (P)
Methyl Orange End
Point (M)

1

2






CALCULATION

Hydroxide ion alkalinity
Volume of HCl (2P-M) = ???????ml

Strength of HCl = ???????? N

Volume of water sample = ???????...ml

Strength of water sample = Volume of HCl (2P-M) x Strength of HCl
Volume of water sample

=

? Hydroxide ion alkalinity in terms of
CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ??????.mg/l







11




b) From the magnitudes of the P & M, the nature of alkalinity can be arrived as follows:

(i) P = M => Presence of only OH
-

(ii) 2P = M => Presence of only CO 3
2-

(iii) P =0, M=0 => Presence of only HCO 3
-
(iv) 2P > M => Presence of OH
-
& CO 3
2-
(v) 2P < M => Presence of HCO 3
-
& CO 3
2-

(Mixture of OH
-
& HCO3
-
is not listed since they do not exist together and are considered equivalent to CO 3
2-
).

PROCEDURE
TITRATION
ESTIMATION OF ALKALINITY IN WATER SAMPLE

Exactly 20 ml of water sample is pipetted out into a clean conical flask. Few drops of phenolphthalein
indicator are added and titrated against a standardized HCl taken in the burette. The end point is the
disappearance of pink colour, which is noted as P. Few drops of methyl orange indicator is added to the same
solution. The solution turns to yellow. The titration is continued further by adding same HCl without break till the
end point is reached. The end point is the colour change from yellow to reddish orange.

The experiment is repeated to get concordant values. From the magnitudes of P & M values, the type of
alkalinity present in the water sample is inferred and the individual amounts are calculated and reported.










12


Carbonate ion alkalinity

Volume of HCl 2 (M ? P) = ??? ????????ml

Strength of HCl = ??.?????..???...N

Volume of water sample =........................................ml

Strength of water sample = Volume of HCl 2 (M ? P) x Strength of HCl
Volume of water sample

= ???????????.. N




? Carbonate ion alkalinity
in terms of CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ???????????mg/l

















13





RESULT

1) The type of alkalinity present in the water sample = -------------------------ions.

2) The individual amounts of alkalinity present in the water sample:
Hydroxide ion alkalinity

= ----------------- ppm
Carbonate ion alkalinity = ------------------ ppm
Bicarbonate ion alkalinity = ----------------- ppm





VIVA-VOCE


1. What is meant by alkalinity?
2. What are the ions responsible for alkalinity?
3. Why OH
-
and HCO 3
?
ions cannot exist together in water?
4. What are the ions responsible for alkalinity when 2P > M?
5. What is the pH range for both in acidic and basic solutions?
6. What is the colour of phenolphthalein in an acid and in an alkaline solution?
7. What is the purpose of using two indicators in same titration?
8. What are the possible combinations of ions for alkalinity?
9. How is the amount of alkalinity expressed?
10. What are the types of indicator used in this experiment?







14

SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II TITRATION III
Standardisation of
EDTA
(EDTA Vs Std
Hard water)
Determination of
total hardness
(Std EDTA Vs Hard
water sample)
Determination of
permanent hardness
(Std EDTA Vs Boiled
Hard water sample)

Burette solution

EDTA solution

EDTA solution

EDTA solution

Pipette solution

20ml Std. hard water

20 ml hard water sample

20ml boiled hard water sample

Indicator

2 drops of EBT

2 drops of EBT

2 drops of EBT

Additional soln.


Ammoniacal Buffer
solution (5ml)

Ammoniacal Buffer solution
(5ml)

Ammoniacal Buffer solution
(5ml)
End point Wine - red to Steel blue Wine - red to steel blue Wine - red to Steel blue




STANDARDISATION OF EDTA
Titration - I
Std. HARD WATER Vs EDTA Indicator: EBT

S. No.
Volume of std hard
water (ml)
Burette Reading Volume of
EDTA
(V 1) (ml)
Concordant value

Initial

Final



Volume of std .hard water taken = 20 ml
Volume of EDTA consumed (V 1) = --------------- ml
1 ml of std.hard water = 1mg of CaCO 3
20 ml of std hard water = 20 mg of CaCO 3

V 1 ml of EDTA solution containing 20 mg of CaCO 3
1 ml of EDTA solution = 20 / V 1 mg of CaCO 3
= -----------------------mg of CaCO 3


15

Expt. No. 2 DETERMINATION OF TOTAL, TEMPORARY AND
PERMANENT HARDNESS OF WATER

AIM
To estimate the amount of total, temporary & permanent hardness in the given sample of water.

PRINCIPLE
The estimation is based on the complexometric titration.

(i) Total hardness of water is estimated by titrating against EDTA using EBT indicator.
EBT+M ?[EBT-M] (unstable complex)
(EBT-M) (Unstable complex) +EDTA ? [EDTA-M] (stable complex) +EBT
EBT indicator forms wine- red colored complex with metal ions present in water. On addition of EDTA
metal ions preferably forms complexes with EDTA and steel blue EBT indicator is set free. Therefore
change of colour from wine- red to steel blue denotes the end point.

(ii) Temporary hardness is removed by boiling the water.
Ca (HCO 3) 2 ? CaCO 3 +CO 2 ?+H 2O
Mg (HCO 3) 2 ? Mg(OH) 2 +2CO 2 ?
The precipitate is filtered and the remaining permanent hardness is estimated using EDTA.

PROCEDURE

TITRATION ? I
STANDARDISATION OF EDTA

Pipette out 20ml of standard hard water into a 250ml conical flask. Add 5ml of buffer solution and 3
drops of eriochrome black T indictor. Titrate the solution with EDTA from the burette until the colour
changes from wine- red to steel blue at the end point. Repeat the titration for concordant values. Let the
titre value be V 1ml.


16


Titration-II
SAMPLE HARD WATER Vs Std EDTA Indicator: EBT

S.No. Volume of sample
hard water (ml)
Burette Reading Volume of
EDTA
(V 2) (ml)
Concordant value

Initial

Final




CALCULATION

Calculation of total hardness


Volume of EDTA consumed (V 2) = ------------------------- ml
1ml of EDTA = 20 / V 1 mg of CaCO 3
V 2 ml of EDTA = 20 / V 1 x V 2 mg of CaCO 3

( i.e), If 20ml of sample hard water contains 20 x V 2 mg of CaCO 3 / V 1

Then 1000ml of water sample = 20 x V 2 x 1000 / V 1 x 20 mg of CaCO 3

= 1000 x V 2 / V 1 mg of CaCO3

Total hardness of given water sample = ---------------------ppm









17



DETERMINATION OF TOTAL HARDNESS

Pipette out 20ml of sample hard water into a clean conical flask. Add 5ml of buffer solution and 4 -5
drops of Eriochrome black -T indicator. Titrate the wine - red coloured solution with EDTA from the burette until
the colour steel blue appears at the end point. Repeat the titration for concordant values. Let the titre value be
V 2ml.



DETERMINATION OF PERMANENT HARDNESS

Take 100ml of hard water sample in a 500ml beaker and boil gently for about 1hour. Cool, filter it into a
100ml standard flask and make the volume up to the mark. Take 20ml of this solution and proceed it in the same
way as in titration (I). The volume of EDTA consumed corresponds to the permanent hardness of the water
sample. Let the titre value be V 3ml. Temporary hardness is calculated by subtracting permanent hardness from
total hardness.





















18




DETERMINATION OF PERMANENT HARDNESS
BOILED SAMPLE WATER Vs Std. EDTA Indicator: EBT


S.No.
Volume of boiled
hard water (ml)
Burette Reading (ml) Volume of
EDTA
(ml)

Concordant value

Initial Final



CALCULATION OF PERMANENT HARDNESS


Volume of EDTA consumed V 3 = ---------------------ml

1ml of EDTA = 20 / V 1 mg of CaCO 3

V 3ml of EDTA = 20 / V 1 x V 3 mg of CaCO 3

(i.e) 20 ml of boiled sample hard water = 20 / V 1 x V 3 mg of CaCO 3

Then 1000ml of boiled water sample = 20 / V 1 x V 3 / 20 * 1000mg of CaCO 3

= 1000 x V 3 / V 1 mg of CaCO 3

permanent hardness of boiled water sample = -----------------ppm

Temporary hardness of the given water sample = Total hardness ? Permanent hardness

= ------------------ppm

19







RESULT

(i) Total hardness of the given sample water = -------------- ppm.
(ii) Permanent hardness of the given sample water = --------------- ppm.
(iii) Temporary hardness of the given sample water = ----------------ppm.







VIVA-VOCE

1. Define ? Hard water
2. What is the structure of EDTA?
3. How will you calculate temporary hardness?
4. What is the role of the buffer in EDTA titration?
5. What is the permissible limit of hardness in drinking water?
6. Name the hardness producing ions present in water.
7. Name two salts which are responsible for temporary hardness.
8. Why is CaCO 3 taken as the standard?
9. Write the expansion of EDTA.
10. What is meant by EBT?











20





SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II
Standardisation of
AgNO 3
Estimation of Chloride
Burette solution

AgNO 3 solution

Std. AgNO 3 solution

Pipette solution

20ml std KCl solution

20 ml water sample

Indicator

1ml K 2CrO 4

1ml K 2CrO 4


End point

yellow to reddish brown

yellow to reddish brown

Titration I
Std. AgNO3 Vs KCl Indicator: Potassium Chromate













CALCULATION

Volume of KCl (V 1) = ------- ml

Strength of KCl (N 1) = ------- N

Volume of Silver Nitrate (V 2) = -------- ml

Strength of Siver Nitrate V 1N 1
N 2 =
V 1

= --------------------- N

S.No.
Volume of KCl
(ml)
Burette Reading (ml)
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

21




Expt.No. 3 ESTIMATION OF CHLORIDE CONTENT IN WATER
(ARGENTOMETRIC METHOD)
AIM
To estimate the amount of chloride present in given water sample by Argentometric method (Mohr?s
method). You are provided with standard solution of NaCl of strength --------N and a approximately N/10 solution of
Silver nitrate.

PRINCIPLE
The Chloride ion in the form of NaCl, KCl, CaCl 2, MgCl 2 etc., present in the water sample can be estimated
by Argentometric method or known as Mohr?s method. It is an example for precipitation titration. The reaction
between std. Sodium chloride and Silver nitrate is given below.
AgNO 3 + NaCl ? AgCl ? + NaNO 3
The completion of reaction can be observed by employing potassium chromate as the indicator. The end
point is the colour change from yellow to reddish brown due to the following reaction.
2AgNO 3 + K 2CrO 4 ? Ag 2CrO 4 ? + 2KNO 3
Potassium chromate indicator will not be precipitated as silver chromate until all the chlorides in the solution
have been precipitated as AgCl Since a precipitation reaction takes place in preference, this reaction takes place
only at the end point.

PROCEDURE
TITRATION I: STANDARDISATION OF SILVER NITRATE
Pipette out 20ml of standard sodium or potassium chloride solution into a clean conical flask. Add 1ml of 5%
K 2CrO 4 indicator, as the solution turns yellow in colour. Titrate it against silver nitrate solution taken in the burette.
Observe the nearness of the end point through the formation of coagulated silver chloride precipitate at the bottom
of the flask. Now add the silver nitrate drop by drop until the solution gets a faint reddish brown tinge. Repeat the
titration for concordant value. Let the volume of silver nitrate be V 2ml.





22






TITRATION - II

Std AgNO3 Vs WATER SAMPLE Indicator: Potassium Chromate













CALCULATION

Volume of Silver Nitrate (V 3) = ------------ ml

Strength of Siver Nitrate (N 3) = ------------- N

Volume of Water sample (V 4) = -------------- ml

Strength of Water sample V 3 N 3
(N 4) =
V 4

= ----------------- N

Amount of Chloride ion present in 1000 ml of the water sample = Equivalent mass of HCl X 1000


= N 4 x 35.46 x 1000


= -----------------mg/l







S.No.
Volume of water
sample (ml)
Burette Reading
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

23





TITRATION - II
ESTIMATION OF CHLORIDE ION

Pipette out 40 ml of the given water sample into a clean conical flask.To this sample add 1ml of 5% K 2CrO 4
indicator and titrate it against the standardized silver nitrate solution taken in the burette and continue the titration
until the solution produces a reddish brown colour. Note down the end point and repeat the titration for
concordance. Let the volume be V 3ml.







RESULT

The amount of chloride ion present in the water sample = ----------------- mg/l.




VIVA-VOCE

1. Why is this method known as Argentometric method?
2.
What is the chemical reaction between AgNO 3 and Cl
-
ions present in water?

3.
What is the form of Chloride ion present in water?

4. What is the reaction between AgNO 3 and K 2CrO 4 ?
5. What is the name of the method used in this titration?
6. Name the link solution used in the determination.
7. Name the solution used to standardize AgNO 3.
8. What is the indicator used in the determination?
9. How will you calculate the amount of chloride ion in the given solution?
10. What is the colour change in the titration?




24




SHORT PROCEDURE


CONTENTS

TITRATION I

TITRATION II
Burette solution

Std Sodium Hydroxide

Std Sodium Hydroxide

Pipette solution

20 ml hydrochloric acid 20 ml hydrochloric acid
Additional solution


20 ml distilled water

20 ml distilled water


End point



Sudden increase in pH
pH gradual increase

Equivalent Weight of HCl = 36.5







ROUGH GRAPH FAIR GRAPH











pH
? pH/ ? V





Volume of NaOH
(ml)
Volume of NaOH
(ml)





25



Expt. No. 4 DETERMINATION OF STRENGTH OF HCl by pH METRY

AIM
To determine the strength of given HCl by pH metry. A standard solution of 0.1N NaOH is provided.

PRINCIPLE
The pH of a solution is related to H
+
ion concentration by the following formula.

. pH = -log [ H
+
]

pH of a solution is indirectly related to H
+
ion concentration. When NaOH is added slowly to HCl, H
+
ions
get neutralized by OH
-
ions. The pH increases slowly.

H
+
+ Cl
-
+ Na
+
+ OH
-
? Na
+
+ Cl
-
+H 2O

When all H
+
ions of HCl are neutralized at the end point, addition of NaOH causes high increase in pH
because of the addition of excess OH
-
ions.

MATERIALS REQUIRED
pH meter, Glass electrode, Burette, Pipette, Std.NaOH, approximately N/10 HCl .

PROCEDURE

The burette is washed with distilled water, rinsed with the given std. Sodium hydroxide and filled with the
same solution. Exactly 10ml of the given HCl solution is pipetted out into a clean beaker. It is then diluted to 50ml
with distilled water. A glass electrode is dipped into the solution and its terminals are connected to a pH meter.

26

TITRATION - I
S.No Volume of
NaOH (ml)
pH
1

2

3

4

5

6

7

8

9

10


TITRATION - II



CALCULATION

Volume of NaOH (V 1) = ------------------- ml ( titre value)
Strength of NaOH (N 1) = ------------------- N
Volume of HCl (V 2) = ------------------ml
Strength of HCl (N 2) = ------------------ N
N 2 = V 1 N 1 / V 2
Strength of HCl = -------------------- N
Amount of HCl present in 1000ml of the given solution = Strength x equivalent weight of HCl
= ------------------ X 36.5
= --------------------- g
S.No Volume of
NaOH (ml)
pH
11

12

13

14

15

16

17

18

19

20

S.No
Volume of
NaOH (ml)
pH ?pH ?V ?pH / ?V
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
27



Now NaOH is gradually added from the burette to HCl taken in the beaker. pH of the solution is noted for
each addition of NaOH. This process is continued until 5 readings are taken after the end point.
A fair titration is performed to find the exact end point.





RESULT

(i) Strength of the given HCl solution = ---------------- N
(ii) Amount of HCl present in a litre of the solution = ---------------- g


VIVA-VOCE

1. What is meant by pH?
2. What is the name of the reference electrode used ?
3. Why does pH value increase suddenly at the end point?
4. What is the indicator used in the titration?
5. What is the pH range of human blood?
6. What is the unit of pH?
7. How will you calculate the amount of HCl?
8. How is glass electrode represented?
9. Why is glass electrode known as ion selective electrode?
10. What is the chemical reaction involved in this titration?





28




SHORT PROCEDURE


CONTENTS
TITRATION
Burette solution

Std Sodium Hydroxide

Pipette solution

20 ml mixture of acid (HCl+ CH 3COOH)


Additional solution

20 ml distilled water


End point

Conductivity decreases-slowly increases-Sudden increase



Equivalent Weight of HCl = 36.5


Equivalent Weight of CH 3COOH = 60



MODEL GRAPH


Conductance
Volume of NaOH
Mixture of Acids






29




Expt. No. 5 CONDUCTOMETRIC TITRATION OF MIXTURE
OF ACIDS

AIM
To determine the amount of a strong acid and a weak acid present in the given solution.

PRINCIPLE

Solution of electrolytes conducts electricity due to the presence of ions. Since specific conductance of a
solution is proportional to the concentration of ions in it, conductance of the solution is measured during the titration.

HCl + NaOH ? NaCl + H 2O (I neutralization)

CH 3COOH + NaOH ? CH 3COONa + H 2O (II neutralization)

When a solution of HCl is treated with NaOH the fast moving hydrogen ions are progressively replaced by
slow moving sodium ions. As a result conductance of the solution decreases. This decrease will take place until the
first neutralisation point is reached. Further addition of alkali results in formation of sodium acetate.

Since sodium acetate is stronger than acetic acid conductivity slowly increases until all acetic acid is
completely neutralized.(II Neutralisation) This is due to the presence of fast moving OH
-
ions. Anymore addition of
alkali increases the conductance sharply.

PROCEDURE
The burette is filled with NaOH solution upto zero mark. The given unknown solution (mixture of a weak &
a strong acid) is transferred into a 100ml standard flask and made upto the mark with distilled water. 20ml of the
made up solution is pipetted out into a clean 100ml beaker. The solution is diluted to 20ml using distilled water. A
conductivity cell is dipped into the solution and the terminals are connected to a conductivity meter.
30


TITRATION


CALCULATION OF STRENGTH OF HCl
Volume of NaOH (V 1) = --------------- ml (titre value)
Strength of NaOH (N 1) = ---------------- N
Volume of HCl (V 2) = ------------ ml
Strength of HCl (N 2) = -------------- N

N 2 = V 1 N 1 / V 2
Strength of HCl = ---------------- N
CALCULATION OF STRENGTH OF CH3COOH
Volume of NaOH (V 1) = ------------ ml (titre value)
Strength of NaOH (N 1) = ------------ N
Volume of CH 3COOH (V 2) = ------------ ml
Strength of CH 3COOH (N 2) = ------------ N
N 2 = V 1 N 1 / V 2

Strength of CH 3COOH = ------------ N



S.No

Volume of NaOH
(ml)

Conductance (mho)

14

15

16

17
18
19
20

21
22
23
24
25
26

S.No

Volume of NaOH
(ml)

Conductance (mho)

1
2
3
4
5
6
7
8
9
10
11
12
13
31

The burette solution is added to the unknown solution in the beaker in 0.5 ml increments, the solution is
stirred using a glass rod, and the observed conductance values are read from the meter. The conductance values
show decrease in the initial values, then gradually increases and finally shows a steep increase. The titration hence
shows two end-points (i.e) I neutralization (weak acid) & II neutralization (strong acid).
The accurate end-point is obtained by plotting a graph between observed conductance Vs volume of
NaOH added.

RESULT
The strength of acids present in the given unknown solution are:
a) Strong acid = ---------------- N
b) Weak acid = -----------------N



VIVA-VOCE

1. What is weak acid?
2. How many end points are obtained from the graph? Comment two end points.
3. Why is the conductance increase in the first end point?
4. What mixture of acids used in this titration?
5. Write the neutralization reaction between CH 3COOH and NaOH.
6. What is the solution present in the conductivity cell?
7. What are strong and weak electrolytes?
8. Give an example for strong acid and weak acid.
9. What is the strong electrolyte of weak electrolyte?
10. Give an example for strong base.









32

SHORT PROCEDURE



















ROUGH GRAPH







EMF(mV)






Volume of Potassium dichromate (ml)

FAIR GRAPH









? E / ? V

Volume of Potassium dichromate (ml)




CONTENTS

TITRATION I

TITRATION II
Burette solution

Std Potassium dichromate

Std Potassium dichromate

Pipette solution

10 ml of FAS


10 ml of FAS



Additional
solution

20 ml distilled water+
10 ml of dil H 2SO 4


20 ml distilled water+
10 ml of dil H 2SO 4

End point

Sudden increase in EMF

EMF increases and decreases

Equivalent Weight of Ferrous ion = 55.85

33


Expt. No. 6 ESTIMATION OF FERROUS ION BY POTENTIOMETRIC
TITRATION

AIM
To estimate the amount of ferrous ion present in whole of the given solution potentiometrically. A standard
solution of potassium dichromate of strength -----------N is provided.

PRINCIPLE

Potentiometric titrations depend on measurement of emf between reference electrode and an indicator
electrode. When a solution of ferrous iron is titrated with a solution of potassium dichromate, the following redox
reaction takes place.

6Fe
2+
+ Cr 2O 7
2-
+ 14 H
+
? 6Fe
3+
+ 2Cr
3+
+ 7H 2O

During this titration Fe
2+
is converted in to Fe
3+
, whose concentration increases. At the end point, there
will be a sharp change due to sudden removal of all Fe
2+
ions.
The cell is set up by connecting this redox electrode with a calomel electrode as shown below:

Pt, Fe
2+
, Fe
3+
, II KCl , HgCl 2 (s), Hg

A graph between EMF measured against the volume of potassium dichromate added is drawn and the
end point is noted from the graph.

PROCEDURE

10ml of Ferrous solution is pipetted out into a 100 ml beaker. 10ml of dil.H 2SO 4 and 20ml of distilled water
are added. A platinum electrode and a calomel electrode are dipped into this solution and connected to the
potentiometer. Then 1ml of potassium dichromate is added to the solution and stirred well for 30 seconds. The
EMF is measured and the titration is continued by adding potassium dichromate in 1ml increments till five
measurements after the end point.



34


ROUGH TITRATION



S.No.

Volume of dichromate (ml)

EMF (mV)


1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.





35







A graph is drawn by plotting the emf against the volume of potassium dichromate and the end point range is
fixed.


About 20ml of Ferrous solution is pipetted out and the titration is continued by adding 0.1ml increaments of
potassium dichromate in the end point range. The emf is measured for each 0.1ml after stirring the solution well.


A graph is plotted between emf and the volume of potassium dichromate and also a first derivative graph is
plotted ( ? E/ ? V against vol. of K 2Cr 2O 7). The strength of Ferrous solution and the amount of Ferrous ion present are
calculated from the end point.



























36

FAIR TITRATION

S.No Volume of
Dichromate (ml)
Emf (mV) ?E ?V ?E/?V






















CALCULATION

Volume of Potassim dichromate (V 1) = -------------- ml
Normality of Potassium dichromate (N 1) = --------------- N
Volume of Ferrous sulphate (V 2) = --------------- ml
Normality of Ferrous sulphate (N 2) = --------------- N
Amount of Ferrous ion present in 1000ml of the solution = Normality X Equivalent weight of ferrous ion
= --------------- X 55.85 g

The amount of Ferrous ion present in the given solution = ----------------- g






37









RESULT

The amount of Ferrous ion present in the whole of the given solution = --------------- g.








VIVA-VOCE

1. What is EMF?
2. What is the basic principle of potentiometric titration?
3. Why does EMF increase during the titration?
4. Write the cell representation of the titration.
5. What is redox reaction?
6. What is the purpose of adding sulphuric acid?
7. What are the advantages of potentiometric titration?
8. How will you obtain the end point in the titration?
9. What is the name of the indicator electrode used in this titration?
10. What is the name of the reference electrode used?








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?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





3


PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)
1. Fundamentals
To provide students with a solid foundation in Mathematics, Science and fundamentals of engineering,
enabling them to apply, to find solutions for engineering problems and use this knowledge to acquire higher
education
2. Core Competence
To train the students in chemistry practicals so that they apply their knowledge and training to compare,
and to analyze various engineering industrial problems to find solutions
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice this enables
them to find solutions for the real time problems in industry, and to design products
4. Professionalism
To inculcate professional and effective communication skills, leadership qualities and team spirit in the
students to make them multi-faceted personalities and develop their ability to relate engineering issues to
broader social context
5. Lifelong Learning/Ethics
To demonstrate and practice ethical and professional responsibilities in the industry and society in the
large, through commitment and lifelong learning needed for successful professional career






4


PROGRAMME OUTCOMES (POs)
To demonstrate and apply knowledge of Mathematics, Science and engineering fundamentals in the following
experiments.
1 .To estimate HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. To determine total, temporary & permanent hardness of water by EDTA method.
3. To determine DO content of water sample by Winkler?s method.
4. To determine chloride content of water sample by Argentometric method.
5. To estimate copper content of the given solution by Iodometry.
6. To determine strength of given hydrochloric acid using pH meter.
7. To determine strength of acids in a mixture of acids using conductivity meter.
8. To determine iron content of the given solution using potentiometer.
9. To estimate iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. To estimate sodium and potassium present in water using flame photometer.
11. To determine molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. To determine Pseudo first order kinetics ? ester hydrolysis.
13. To determine Corrosion experiment ? weight loss method.
14. To estimate CMC.
15. To estimate Phase change in a solid.
16. To determine strength of strong acid vs strong base using conductivity meter.











5

BS8161 - CHEMISTRY LABORATORY
SYLLABUS


? To make the student to acquire practical skills in the determination of water quality
parameters through volumetric and instrumental analysis.

? ???? ??? ???? ?? ???? ? ? ?To acquaint the students with the determination of molecular weight of a polymer by
viscometery.

LIST OF EXPERIMENTS:
1. Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. Determination of total, temporary & permanent hardness of water by EDTA method.
3. Determination of DO content of water sample by Winkler?s method.
4. Determination of chloride content of water sample by Argentometric method.
5. Estimation of copper content of the given solution by Iodometry.
6. Determination of strength of given hydrochloric acid using pH meter.
7. Determination of strength of acids in a mixture of acids using conductivity meter.
8. Estimation of iron content of the given solution using potentiometer.
9. Estimation of iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. Estimation of sodium and potassium present in water using flame photometer.
11. Determination of molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. Pseudo first order kinetics ? ester hydrolysis.
13. Corrosion experiment ? weight loss method.
14. Determination of CMC.
15. Phase change in a solid.
16. Conductometric titration of strong acid vs strong base.




? The students will be outfitted with hands-on knowledge in the quantitative chemical
analysis of water quality related parameters.
COURSE OBJECTIVES
COURSE OUTCOMES
6


INDEX [ SEMESTER ? I ]


S.No.



Date


Experiment

Date of
submission



Mark


Signature

1.

Estimation of HCl using Na 2CO 3 as
primary standard and Determination of
alkalinity in water sample.



2.


Determination of total, temporary &
permanent hardness of water by EDTA
method.



3.


Determination of chloride content of water
sample by argentometric method.



4.


Determination of strength of given
hydrochloric acid using pH meter.



5.


Determination of strength of acids in a
mixture of acids using conductivity meter.



6.


Estimation of iron content of the given
solution using potentiometer.



7.





Conductometric titration of strong acid Vs
strong base.



8.



Estimation of copper content of the given
solution by Iodometry


9.
Estimation of sodium and potassium
present in water using flame photometer




7




CONTENTS


S.No.


NAME OF EXPERIMENT

PAGE
No.
SEMESTER - I
1.
Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in
water sample.
09
2. Determination of total, temporary & permanent hardness of water by EDTA method. 15
3. Determination of chloride content of water sample by Argentometric method. 21
4. Determination of strength of given hydrochloric acid using pH meter. 25
5. Determination of strength of acids in a mixture of acids using conductivity meter. 29
6. Estimation of iron content of the given solution using potentiometer. 33
7. Conductometric titration of strong acid Vs strong base.

39


42

8


Estimation of copper content of the given solution by Iodometry 43
9 Estimation of sodium and potassium present in water using flame photometer 47






8



SHORT PROCEDURE:

CONTENTS
TITRATION
Estimation of alkalinity in water sample
(Std HCl Vs water sample)

Burette solution

Std. HCl


Pipette solution

Water sample


Indicator


(i) Phenolphthalein
(ii) Methyl orange


End point

(i) Disappearance of pink colour
(ii) Appearance of reddish orange colour






Relationship
between P &M
Nature of alkalinity
Amount of individual
alkalinities
OH
-
HCO 3
-


CO 3
2-

P = M

only OH
-

P or M

?
0.0

0.0


2P = M

only CO 3
2-


2P or M


0.0


0.0


?

P =0, M?0

only HCO 3
-



M



0.0



?

0.0


2P > M


OH
-
&CO 3
2-


OH
-
= 2P-M
CO 3
2-
= 2(M-P)


?

0.0

?

P < ? M




HCO 3
-
&CO 3
2-


HCO 3
-
= M-2P
CO 3
2-
= 2P

0.0 ? ?




9





Expt. No. 1 DETERMINATION OF ALKALINITY IN WATER
AIM
To determine the type and amounts of alkalinity in the given water sample. A standard solution of Na 2CO 3
of strength ____N is given.

PRINCIPLE
Alkalinity in water is due to the presence of soluble hydroxides, bicarbonates and carbonates.
Determination of various types and amounts of alkalinity is easily carried out by titration with standard HCl
employing the indicators phenolphthalein and methyl orange independently or in succession.

The following reactions occur when different types of alkalinity are neutralized with acid.

OH
?
+ H
+
? H 2O completed at pH 8.2-9.0 ----- (1)

CO 3
2 ?
+ H
+
? HCO 3
?
----- (2)

HCO 3
?
+ H
+
? (H 2CO 3) ? H 2O + CO 2, completed at pH 4.2-5.5 ----- (3)

Neutralisation (1) & (2) will be notified by phenolphthalein end-point while all the three will be

accounted by
methyl orange end-point. Bicarbonate in eqn. (3) may be due to the existence of soluble free bicarbonate salts and
bicarbonates resulting from half neutralization of soluble carbonates (eqn. (2))

Various steps to be followed

a) A known volume of water sample is titrated against std. HCl using first phenolphthalein indicator till
end-point (P) and the titration is continued without break using methyl orange indicator till the end-
point (M).



10


Titration

Estimation of Alkalinity in water sample

Standard HCl Vs Water sample Indicator: 1. Phenolphthalein
2. Methyl Orange


S.No.
Volume
of water
sample (ml)
Burette Reading
Concordant value

Initial Phenolphthalein End
Point (P)
Methyl Orange End
Point (M)

1

2






CALCULATION

Hydroxide ion alkalinity
Volume of HCl (2P-M) = ???????ml

Strength of HCl = ???????? N

Volume of water sample = ???????...ml

Strength of water sample = Volume of HCl (2P-M) x Strength of HCl
Volume of water sample

=

? Hydroxide ion alkalinity in terms of
CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ??????.mg/l







11




b) From the magnitudes of the P & M, the nature of alkalinity can be arrived as follows:

(i) P = M => Presence of only OH
-

(ii) 2P = M => Presence of only CO 3
2-

(iii) P =0, M=0 => Presence of only HCO 3
-
(iv) 2P > M => Presence of OH
-
& CO 3
2-
(v) 2P < M => Presence of HCO 3
-
& CO 3
2-

(Mixture of OH
-
& HCO3
-
is not listed since they do not exist together and are considered equivalent to CO 3
2-
).

PROCEDURE
TITRATION
ESTIMATION OF ALKALINITY IN WATER SAMPLE

Exactly 20 ml of water sample is pipetted out into a clean conical flask. Few drops of phenolphthalein
indicator are added and titrated against a standardized HCl taken in the burette. The end point is the
disappearance of pink colour, which is noted as P. Few drops of methyl orange indicator is added to the same
solution. The solution turns to yellow. The titration is continued further by adding same HCl without break till the
end point is reached. The end point is the colour change from yellow to reddish orange.

The experiment is repeated to get concordant values. From the magnitudes of P & M values, the type of
alkalinity present in the water sample is inferred and the individual amounts are calculated and reported.










12


Carbonate ion alkalinity

Volume of HCl 2 (M ? P) = ??? ????????ml

Strength of HCl = ??.?????..???...N

Volume of water sample =........................................ml

Strength of water sample = Volume of HCl 2 (M ? P) x Strength of HCl
Volume of water sample

= ???????????.. N




? Carbonate ion alkalinity
in terms of CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ???????????mg/l

















13





RESULT

1) The type of alkalinity present in the water sample = -------------------------ions.

2) The individual amounts of alkalinity present in the water sample:
Hydroxide ion alkalinity

= ----------------- ppm
Carbonate ion alkalinity = ------------------ ppm
Bicarbonate ion alkalinity = ----------------- ppm





VIVA-VOCE


1. What is meant by alkalinity?
2. What are the ions responsible for alkalinity?
3. Why OH
-
and HCO 3
?
ions cannot exist together in water?
4. What are the ions responsible for alkalinity when 2P > M?
5. What is the pH range for both in acidic and basic solutions?
6. What is the colour of phenolphthalein in an acid and in an alkaline solution?
7. What is the purpose of using two indicators in same titration?
8. What are the possible combinations of ions for alkalinity?
9. How is the amount of alkalinity expressed?
10. What are the types of indicator used in this experiment?







14

SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II TITRATION III
Standardisation of
EDTA
(EDTA Vs Std
Hard water)
Determination of
total hardness
(Std EDTA Vs Hard
water sample)
Determination of
permanent hardness
(Std EDTA Vs Boiled
Hard water sample)

Burette solution

EDTA solution

EDTA solution

EDTA solution

Pipette solution

20ml Std. hard water

20 ml hard water sample

20ml boiled hard water sample

Indicator

2 drops of EBT

2 drops of EBT

2 drops of EBT

Additional soln.


Ammoniacal Buffer
solution (5ml)

Ammoniacal Buffer solution
(5ml)

Ammoniacal Buffer solution
(5ml)
End point Wine - red to Steel blue Wine - red to steel blue Wine - red to Steel blue




STANDARDISATION OF EDTA
Titration - I
Std. HARD WATER Vs EDTA Indicator: EBT

S. No.
Volume of std hard
water (ml)
Burette Reading Volume of
EDTA
(V 1) (ml)
Concordant value

Initial

Final



Volume of std .hard water taken = 20 ml
Volume of EDTA consumed (V 1) = --------------- ml
1 ml of std.hard water = 1mg of CaCO 3
20 ml of std hard water = 20 mg of CaCO 3

V 1 ml of EDTA solution containing 20 mg of CaCO 3
1 ml of EDTA solution = 20 / V 1 mg of CaCO 3
= -----------------------mg of CaCO 3


15

Expt. No. 2 DETERMINATION OF TOTAL, TEMPORARY AND
PERMANENT HARDNESS OF WATER

AIM
To estimate the amount of total, temporary & permanent hardness in the given sample of water.

PRINCIPLE
The estimation is based on the complexometric titration.

(i) Total hardness of water is estimated by titrating against EDTA using EBT indicator.
EBT+M ?[EBT-M] (unstable complex)
(EBT-M) (Unstable complex) +EDTA ? [EDTA-M] (stable complex) +EBT
EBT indicator forms wine- red colored complex with metal ions present in water. On addition of EDTA
metal ions preferably forms complexes with EDTA and steel blue EBT indicator is set free. Therefore
change of colour from wine- red to steel blue denotes the end point.

(ii) Temporary hardness is removed by boiling the water.
Ca (HCO 3) 2 ? CaCO 3 +CO 2 ?+H 2O
Mg (HCO 3) 2 ? Mg(OH) 2 +2CO 2 ?
The precipitate is filtered and the remaining permanent hardness is estimated using EDTA.

PROCEDURE

TITRATION ? I
STANDARDISATION OF EDTA

Pipette out 20ml of standard hard water into a 250ml conical flask. Add 5ml of buffer solution and 3
drops of eriochrome black T indictor. Titrate the solution with EDTA from the burette until the colour
changes from wine- red to steel blue at the end point. Repeat the titration for concordant values. Let the
titre value be V 1ml.


16


Titration-II
SAMPLE HARD WATER Vs Std EDTA Indicator: EBT

S.No. Volume of sample
hard water (ml)
Burette Reading Volume of
EDTA
(V 2) (ml)
Concordant value

Initial

Final




CALCULATION

Calculation of total hardness


Volume of EDTA consumed (V 2) = ------------------------- ml
1ml of EDTA = 20 / V 1 mg of CaCO 3
V 2 ml of EDTA = 20 / V 1 x V 2 mg of CaCO 3

( i.e), If 20ml of sample hard water contains 20 x V 2 mg of CaCO 3 / V 1

Then 1000ml of water sample = 20 x V 2 x 1000 / V 1 x 20 mg of CaCO 3

= 1000 x V 2 / V 1 mg of CaCO3

Total hardness of given water sample = ---------------------ppm









17



DETERMINATION OF TOTAL HARDNESS

Pipette out 20ml of sample hard water into a clean conical flask. Add 5ml of buffer solution and 4 -5
drops of Eriochrome black -T indicator. Titrate the wine - red coloured solution with EDTA from the burette until
the colour steel blue appears at the end point. Repeat the titration for concordant values. Let the titre value be
V 2ml.



DETERMINATION OF PERMANENT HARDNESS

Take 100ml of hard water sample in a 500ml beaker and boil gently for about 1hour. Cool, filter it into a
100ml standard flask and make the volume up to the mark. Take 20ml of this solution and proceed it in the same
way as in titration (I). The volume of EDTA consumed corresponds to the permanent hardness of the water
sample. Let the titre value be V 3ml. Temporary hardness is calculated by subtracting permanent hardness from
total hardness.





















18




DETERMINATION OF PERMANENT HARDNESS
BOILED SAMPLE WATER Vs Std. EDTA Indicator: EBT


S.No.
Volume of boiled
hard water (ml)
Burette Reading (ml) Volume of
EDTA
(ml)

Concordant value

Initial Final



CALCULATION OF PERMANENT HARDNESS


Volume of EDTA consumed V 3 = ---------------------ml

1ml of EDTA = 20 / V 1 mg of CaCO 3

V 3ml of EDTA = 20 / V 1 x V 3 mg of CaCO 3

(i.e) 20 ml of boiled sample hard water = 20 / V 1 x V 3 mg of CaCO 3

Then 1000ml of boiled water sample = 20 / V 1 x V 3 / 20 * 1000mg of CaCO 3

= 1000 x V 3 / V 1 mg of CaCO 3

permanent hardness of boiled water sample = -----------------ppm

Temporary hardness of the given water sample = Total hardness ? Permanent hardness

= ------------------ppm

19







RESULT

(i) Total hardness of the given sample water = -------------- ppm.
(ii) Permanent hardness of the given sample water = --------------- ppm.
(iii) Temporary hardness of the given sample water = ----------------ppm.







VIVA-VOCE

1. Define ? Hard water
2. What is the structure of EDTA?
3. How will you calculate temporary hardness?
4. What is the role of the buffer in EDTA titration?
5. What is the permissible limit of hardness in drinking water?
6. Name the hardness producing ions present in water.
7. Name two salts which are responsible for temporary hardness.
8. Why is CaCO 3 taken as the standard?
9. Write the expansion of EDTA.
10. What is meant by EBT?











20





SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II
Standardisation of
AgNO 3
Estimation of Chloride
Burette solution

AgNO 3 solution

Std. AgNO 3 solution

Pipette solution

20ml std KCl solution

20 ml water sample

Indicator

1ml K 2CrO 4

1ml K 2CrO 4


End point

yellow to reddish brown

yellow to reddish brown

Titration I
Std. AgNO3 Vs KCl Indicator: Potassium Chromate













CALCULATION

Volume of KCl (V 1) = ------- ml

Strength of KCl (N 1) = ------- N

Volume of Silver Nitrate (V 2) = -------- ml

Strength of Siver Nitrate V 1N 1
N 2 =
V 1

= --------------------- N

S.No.
Volume of KCl
(ml)
Burette Reading (ml)
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

21




Expt.No. 3 ESTIMATION OF CHLORIDE CONTENT IN WATER
(ARGENTOMETRIC METHOD)
AIM
To estimate the amount of chloride present in given water sample by Argentometric method (Mohr?s
method). You are provided with standard solution of NaCl of strength --------N and a approximately N/10 solution of
Silver nitrate.

PRINCIPLE
The Chloride ion in the form of NaCl, KCl, CaCl 2, MgCl 2 etc., present in the water sample can be estimated
by Argentometric method or known as Mohr?s method. It is an example for precipitation titration. The reaction
between std. Sodium chloride and Silver nitrate is given below.
AgNO 3 + NaCl ? AgCl ? + NaNO 3
The completion of reaction can be observed by employing potassium chromate as the indicator. The end
point is the colour change from yellow to reddish brown due to the following reaction.
2AgNO 3 + K 2CrO 4 ? Ag 2CrO 4 ? + 2KNO 3
Potassium chromate indicator will not be precipitated as silver chromate until all the chlorides in the solution
have been precipitated as AgCl Since a precipitation reaction takes place in preference, this reaction takes place
only at the end point.

PROCEDURE
TITRATION I: STANDARDISATION OF SILVER NITRATE
Pipette out 20ml of standard sodium or potassium chloride solution into a clean conical flask. Add 1ml of 5%
K 2CrO 4 indicator, as the solution turns yellow in colour. Titrate it against silver nitrate solution taken in the burette.
Observe the nearness of the end point through the formation of coagulated silver chloride precipitate at the bottom
of the flask. Now add the silver nitrate drop by drop until the solution gets a faint reddish brown tinge. Repeat the
titration for concordant value. Let the volume of silver nitrate be V 2ml.





22






TITRATION - II

Std AgNO3 Vs WATER SAMPLE Indicator: Potassium Chromate













CALCULATION

Volume of Silver Nitrate (V 3) = ------------ ml

Strength of Siver Nitrate (N 3) = ------------- N

Volume of Water sample (V 4) = -------------- ml

Strength of Water sample V 3 N 3
(N 4) =
V 4

= ----------------- N

Amount of Chloride ion present in 1000 ml of the water sample = Equivalent mass of HCl X 1000


= N 4 x 35.46 x 1000


= -----------------mg/l







S.No.
Volume of water
sample (ml)
Burette Reading
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

23





TITRATION - II
ESTIMATION OF CHLORIDE ION

Pipette out 40 ml of the given water sample into a clean conical flask.To this sample add 1ml of 5% K 2CrO 4
indicator and titrate it against the standardized silver nitrate solution taken in the burette and continue the titration
until the solution produces a reddish brown colour. Note down the end point and repeat the titration for
concordance. Let the volume be V 3ml.







RESULT

The amount of chloride ion present in the water sample = ----------------- mg/l.




VIVA-VOCE

1. Why is this method known as Argentometric method?
2.
What is the chemical reaction between AgNO 3 and Cl
-
ions present in water?

3.
What is the form of Chloride ion present in water?

4. What is the reaction between AgNO 3 and K 2CrO 4 ?
5. What is the name of the method used in this titration?
6. Name the link solution used in the determination.
7. Name the solution used to standardize AgNO 3.
8. What is the indicator used in the determination?
9. How will you calculate the amount of chloride ion in the given solution?
10. What is the colour change in the titration?




24




SHORT PROCEDURE


CONTENTS

TITRATION I

TITRATION II
Burette solution

Std Sodium Hydroxide

Std Sodium Hydroxide

Pipette solution

20 ml hydrochloric acid 20 ml hydrochloric acid
Additional solution


20 ml distilled water

20 ml distilled water


End point



Sudden increase in pH
pH gradual increase

Equivalent Weight of HCl = 36.5







ROUGH GRAPH FAIR GRAPH











pH
? pH/ ? V





Volume of NaOH
(ml)
Volume of NaOH
(ml)





25



Expt. No. 4 DETERMINATION OF STRENGTH OF HCl by pH METRY

AIM
To determine the strength of given HCl by pH metry. A standard solution of 0.1N NaOH is provided.

PRINCIPLE
The pH of a solution is related to H
+
ion concentration by the following formula.

. pH = -log [ H
+
]

pH of a solution is indirectly related to H
+
ion concentration. When NaOH is added slowly to HCl, H
+
ions
get neutralized by OH
-
ions. The pH increases slowly.

H
+
+ Cl
-
+ Na
+
+ OH
-
? Na
+
+ Cl
-
+H 2O

When all H
+
ions of HCl are neutralized at the end point, addition of NaOH causes high increase in pH
because of the addition of excess OH
-
ions.

MATERIALS REQUIRED
pH meter, Glass electrode, Burette, Pipette, Std.NaOH, approximately N/10 HCl .

PROCEDURE

The burette is washed with distilled water, rinsed with the given std. Sodium hydroxide and filled with the
same solution. Exactly 10ml of the given HCl solution is pipetted out into a clean beaker. It is then diluted to 50ml
with distilled water. A glass electrode is dipped into the solution and its terminals are connected to a pH meter.

26

TITRATION - I
S.No Volume of
NaOH (ml)
pH
1

2

3

4

5

6

7

8

9

10


TITRATION - II



CALCULATION

Volume of NaOH (V 1) = ------------------- ml ( titre value)
Strength of NaOH (N 1) = ------------------- N
Volume of HCl (V 2) = ------------------ml
Strength of HCl (N 2) = ------------------ N
N 2 = V 1 N 1 / V 2
Strength of HCl = -------------------- N
Amount of HCl present in 1000ml of the given solution = Strength x equivalent weight of HCl
= ------------------ X 36.5
= --------------------- g
S.No Volume of
NaOH (ml)
pH
11

12

13

14

15

16

17

18

19

20

S.No
Volume of
NaOH (ml)
pH ?pH ?V ?pH / ?V
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
27



Now NaOH is gradually added from the burette to HCl taken in the beaker. pH of the solution is noted for
each addition of NaOH. This process is continued until 5 readings are taken after the end point.
A fair titration is performed to find the exact end point.





RESULT

(i) Strength of the given HCl solution = ---------------- N
(ii) Amount of HCl present in a litre of the solution = ---------------- g


VIVA-VOCE

1. What is meant by pH?
2. What is the name of the reference electrode used ?
3. Why does pH value increase suddenly at the end point?
4. What is the indicator used in the titration?
5. What is the pH range of human blood?
6. What is the unit of pH?
7. How will you calculate the amount of HCl?
8. How is glass electrode represented?
9. Why is glass electrode known as ion selective electrode?
10. What is the chemical reaction involved in this titration?





28




SHORT PROCEDURE


CONTENTS
TITRATION
Burette solution

Std Sodium Hydroxide

Pipette solution

20 ml mixture of acid (HCl+ CH 3COOH)


Additional solution

20 ml distilled water


End point

Conductivity decreases-slowly increases-Sudden increase



Equivalent Weight of HCl = 36.5


Equivalent Weight of CH 3COOH = 60



MODEL GRAPH


Conductance
Volume of NaOH
Mixture of Acids






29




Expt. No. 5 CONDUCTOMETRIC TITRATION OF MIXTURE
OF ACIDS

AIM
To determine the amount of a strong acid and a weak acid present in the given solution.

PRINCIPLE

Solution of electrolytes conducts electricity due to the presence of ions. Since specific conductance of a
solution is proportional to the concentration of ions in it, conductance of the solution is measured during the titration.

HCl + NaOH ? NaCl + H 2O (I neutralization)

CH 3COOH + NaOH ? CH 3COONa + H 2O (II neutralization)

When a solution of HCl is treated with NaOH the fast moving hydrogen ions are progressively replaced by
slow moving sodium ions. As a result conductance of the solution decreases. This decrease will take place until the
first neutralisation point is reached. Further addition of alkali results in formation of sodium acetate.

Since sodium acetate is stronger than acetic acid conductivity slowly increases until all acetic acid is
completely neutralized.(II Neutralisation) This is due to the presence of fast moving OH
-
ions. Anymore addition of
alkali increases the conductance sharply.

PROCEDURE
The burette is filled with NaOH solution upto zero mark. The given unknown solution (mixture of a weak &
a strong acid) is transferred into a 100ml standard flask and made upto the mark with distilled water. 20ml of the
made up solution is pipetted out into a clean 100ml beaker. The solution is diluted to 20ml using distilled water. A
conductivity cell is dipped into the solution and the terminals are connected to a conductivity meter.
30


TITRATION


CALCULATION OF STRENGTH OF HCl
Volume of NaOH (V 1) = --------------- ml (titre value)
Strength of NaOH (N 1) = ---------------- N
Volume of HCl (V 2) = ------------ ml
Strength of HCl (N 2) = -------------- N

N 2 = V 1 N 1 / V 2
Strength of HCl = ---------------- N
CALCULATION OF STRENGTH OF CH3COOH
Volume of NaOH (V 1) = ------------ ml (titre value)
Strength of NaOH (N 1) = ------------ N
Volume of CH 3COOH (V 2) = ------------ ml
Strength of CH 3COOH (N 2) = ------------ N
N 2 = V 1 N 1 / V 2

Strength of CH 3COOH = ------------ N



S.No

Volume of NaOH
(ml)

Conductance (mho)

14

15

16

17
18
19
20

21
22
23
24
25
26

S.No

Volume of NaOH
(ml)

Conductance (mho)

1
2
3
4
5
6
7
8
9
10
11
12
13
31

The burette solution is added to the unknown solution in the beaker in 0.5 ml increments, the solution is
stirred using a glass rod, and the observed conductance values are read from the meter. The conductance values
show decrease in the initial values, then gradually increases and finally shows a steep increase. The titration hence
shows two end-points (i.e) I neutralization (weak acid) & II neutralization (strong acid).
The accurate end-point is obtained by plotting a graph between observed conductance Vs volume of
NaOH added.

RESULT
The strength of acids present in the given unknown solution are:
a) Strong acid = ---------------- N
b) Weak acid = -----------------N



VIVA-VOCE

1. What is weak acid?
2. How many end points are obtained from the graph? Comment two end points.
3. Why is the conductance increase in the first end point?
4. What mixture of acids used in this titration?
5. Write the neutralization reaction between CH 3COOH and NaOH.
6. What is the solution present in the conductivity cell?
7. What are strong and weak electrolytes?
8. Give an example for strong acid and weak acid.
9. What is the strong electrolyte of weak electrolyte?
10. Give an example for strong base.









32

SHORT PROCEDURE



















ROUGH GRAPH







EMF(mV)






Volume of Potassium dichromate (ml)

FAIR GRAPH









? E / ? V

Volume of Potassium dichromate (ml)




CONTENTS

TITRATION I

TITRATION II
Burette solution

Std Potassium dichromate

Std Potassium dichromate

Pipette solution

10 ml of FAS


10 ml of FAS



Additional
solution

20 ml distilled water+
10 ml of dil H 2SO 4


20 ml distilled water+
10 ml of dil H 2SO 4

End point

Sudden increase in EMF

EMF increases and decreases

Equivalent Weight of Ferrous ion = 55.85

33


Expt. No. 6 ESTIMATION OF FERROUS ION BY POTENTIOMETRIC
TITRATION

AIM
To estimate the amount of ferrous ion present in whole of the given solution potentiometrically. A standard
solution of potassium dichromate of strength -----------N is provided.

PRINCIPLE

Potentiometric titrations depend on measurement of emf between reference electrode and an indicator
electrode. When a solution of ferrous iron is titrated with a solution of potassium dichromate, the following redox
reaction takes place.

6Fe
2+
+ Cr 2O 7
2-
+ 14 H
+
? 6Fe
3+
+ 2Cr
3+
+ 7H 2O

During this titration Fe
2+
is converted in to Fe
3+
, whose concentration increases. At the end point, there
will be a sharp change due to sudden removal of all Fe
2+
ions.
The cell is set up by connecting this redox electrode with a calomel electrode as shown below:

Pt, Fe
2+
, Fe
3+
, II KCl , HgCl 2 (s), Hg

A graph between EMF measured against the volume of potassium dichromate added is drawn and the
end point is noted from the graph.

PROCEDURE

10ml of Ferrous solution is pipetted out into a 100 ml beaker. 10ml of dil.H 2SO 4 and 20ml of distilled water
are added. A platinum electrode and a calomel electrode are dipped into this solution and connected to the
potentiometer. Then 1ml of potassium dichromate is added to the solution and stirred well for 30 seconds. The
EMF is measured and the titration is continued by adding potassium dichromate in 1ml increments till five
measurements after the end point.



34


ROUGH TITRATION



S.No.

Volume of dichromate (ml)

EMF (mV)


1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.





35







A graph is drawn by plotting the emf against the volume of potassium dichromate and the end point range is
fixed.


About 20ml of Ferrous solution is pipetted out and the titration is continued by adding 0.1ml increaments of
potassium dichromate in the end point range. The emf is measured for each 0.1ml after stirring the solution well.


A graph is plotted between emf and the volume of potassium dichromate and also a first derivative graph is
plotted ( ? E/ ? V against vol. of K 2Cr 2O 7). The strength of Ferrous solution and the amount of Ferrous ion present are
calculated from the end point.



























36

FAIR TITRATION

S.No Volume of
Dichromate (ml)
Emf (mV) ?E ?V ?E/?V






















CALCULATION

Volume of Potassim dichromate (V 1) = -------------- ml
Normality of Potassium dichromate (N 1) = --------------- N
Volume of Ferrous sulphate (V 2) = --------------- ml
Normality of Ferrous sulphate (N 2) = --------------- N
Amount of Ferrous ion present in 1000ml of the solution = Normality X Equivalent weight of ferrous ion
= --------------- X 55.85 g

The amount of Ferrous ion present in the given solution = ----------------- g






37









RESULT

The amount of Ferrous ion present in the whole of the given solution = --------------- g.








VIVA-VOCE

1. What is EMF?
2. What is the basic principle of potentiometric titration?
3. Why does EMF increase during the titration?
4. Write the cell representation of the titration.
5. What is redox reaction?
6. What is the purpose of adding sulphuric acid?
7. What are the advantages of potentiometric titration?
8. How will you obtain the end point in the titration?
9. What is the name of the indicator electrode used in this titration?
10. What is the name of the reference electrode used?








38



SHORT PROCEDURE



CONTENTS

TITRATION
Burette solution

Sodium Hydroxide

Pipette solution

20 ml HCl


Additional solution

20 ml distilled water


End point

Decrease in conductance- increase in conductance

Equivalent Weight of HCl = 36.5
















Conductance

Volume of NaOH ( ml)









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?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





3


PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)
1. Fundamentals
To provide students with a solid foundation in Mathematics, Science and fundamentals of engineering,
enabling them to apply, to find solutions for engineering problems and use this knowledge to acquire higher
education
2. Core Competence
To train the students in chemistry practicals so that they apply their knowledge and training to compare,
and to analyze various engineering industrial problems to find solutions
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice this enables
them to find solutions for the real time problems in industry, and to design products
4. Professionalism
To inculcate professional and effective communication skills, leadership qualities and team spirit in the
students to make them multi-faceted personalities and develop their ability to relate engineering issues to
broader social context
5. Lifelong Learning/Ethics
To demonstrate and practice ethical and professional responsibilities in the industry and society in the
large, through commitment and lifelong learning needed for successful professional career






4


PROGRAMME OUTCOMES (POs)
To demonstrate and apply knowledge of Mathematics, Science and engineering fundamentals in the following
experiments.
1 .To estimate HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. To determine total, temporary & permanent hardness of water by EDTA method.
3. To determine DO content of water sample by Winkler?s method.
4. To determine chloride content of water sample by Argentometric method.
5. To estimate copper content of the given solution by Iodometry.
6. To determine strength of given hydrochloric acid using pH meter.
7. To determine strength of acids in a mixture of acids using conductivity meter.
8. To determine iron content of the given solution using potentiometer.
9. To estimate iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. To estimate sodium and potassium present in water using flame photometer.
11. To determine molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. To determine Pseudo first order kinetics ? ester hydrolysis.
13. To determine Corrosion experiment ? weight loss method.
14. To estimate CMC.
15. To estimate Phase change in a solid.
16. To determine strength of strong acid vs strong base using conductivity meter.











5

BS8161 - CHEMISTRY LABORATORY
SYLLABUS


? To make the student to acquire practical skills in the determination of water quality
parameters through volumetric and instrumental analysis.

? ???? ??? ???? ?? ???? ? ? ?To acquaint the students with the determination of molecular weight of a polymer by
viscometery.

LIST OF EXPERIMENTS:
1. Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. Determination of total, temporary & permanent hardness of water by EDTA method.
3. Determination of DO content of water sample by Winkler?s method.
4. Determination of chloride content of water sample by Argentometric method.
5. Estimation of copper content of the given solution by Iodometry.
6. Determination of strength of given hydrochloric acid using pH meter.
7. Determination of strength of acids in a mixture of acids using conductivity meter.
8. Estimation of iron content of the given solution using potentiometer.
9. Estimation of iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. Estimation of sodium and potassium present in water using flame photometer.
11. Determination of molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. Pseudo first order kinetics ? ester hydrolysis.
13. Corrosion experiment ? weight loss method.
14. Determination of CMC.
15. Phase change in a solid.
16. Conductometric titration of strong acid vs strong base.




? The students will be outfitted with hands-on knowledge in the quantitative chemical
analysis of water quality related parameters.
COURSE OBJECTIVES
COURSE OUTCOMES
6


INDEX [ SEMESTER ? I ]


S.No.



Date


Experiment

Date of
submission



Mark


Signature

1.

Estimation of HCl using Na 2CO 3 as
primary standard and Determination of
alkalinity in water sample.



2.


Determination of total, temporary &
permanent hardness of water by EDTA
method.



3.


Determination of chloride content of water
sample by argentometric method.



4.


Determination of strength of given
hydrochloric acid using pH meter.



5.


Determination of strength of acids in a
mixture of acids using conductivity meter.



6.


Estimation of iron content of the given
solution using potentiometer.



7.





Conductometric titration of strong acid Vs
strong base.



8.



Estimation of copper content of the given
solution by Iodometry


9.
Estimation of sodium and potassium
present in water using flame photometer




7




CONTENTS


S.No.


NAME OF EXPERIMENT

PAGE
No.
SEMESTER - I
1.
Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in
water sample.
09
2. Determination of total, temporary & permanent hardness of water by EDTA method. 15
3. Determination of chloride content of water sample by Argentometric method. 21
4. Determination of strength of given hydrochloric acid using pH meter. 25
5. Determination of strength of acids in a mixture of acids using conductivity meter. 29
6. Estimation of iron content of the given solution using potentiometer. 33
7. Conductometric titration of strong acid Vs strong base.

39


42

8


Estimation of copper content of the given solution by Iodometry 43
9 Estimation of sodium and potassium present in water using flame photometer 47






8



SHORT PROCEDURE:

CONTENTS
TITRATION
Estimation of alkalinity in water sample
(Std HCl Vs water sample)

Burette solution

Std. HCl


Pipette solution

Water sample


Indicator


(i) Phenolphthalein
(ii) Methyl orange


End point

(i) Disappearance of pink colour
(ii) Appearance of reddish orange colour






Relationship
between P &M
Nature of alkalinity
Amount of individual
alkalinities
OH
-
HCO 3
-


CO 3
2-

P = M

only OH
-

P or M

?
0.0

0.0


2P = M

only CO 3
2-


2P or M


0.0


0.0


?

P =0, M?0

only HCO 3
-



M



0.0



?

0.0


2P > M


OH
-
&CO 3
2-


OH
-
= 2P-M
CO 3
2-
= 2(M-P)


?

0.0

?

P < ? M




HCO 3
-
&CO 3
2-


HCO 3
-
= M-2P
CO 3
2-
= 2P

0.0 ? ?




9





Expt. No. 1 DETERMINATION OF ALKALINITY IN WATER
AIM
To determine the type and amounts of alkalinity in the given water sample. A standard solution of Na 2CO 3
of strength ____N is given.

PRINCIPLE
Alkalinity in water is due to the presence of soluble hydroxides, bicarbonates and carbonates.
Determination of various types and amounts of alkalinity is easily carried out by titration with standard HCl
employing the indicators phenolphthalein and methyl orange independently or in succession.

The following reactions occur when different types of alkalinity are neutralized with acid.

OH
?
+ H
+
? H 2O completed at pH 8.2-9.0 ----- (1)

CO 3
2 ?
+ H
+
? HCO 3
?
----- (2)

HCO 3
?
+ H
+
? (H 2CO 3) ? H 2O + CO 2, completed at pH 4.2-5.5 ----- (3)

Neutralisation (1) & (2) will be notified by phenolphthalein end-point while all the three will be

accounted by
methyl orange end-point. Bicarbonate in eqn. (3) may be due to the existence of soluble free bicarbonate salts and
bicarbonates resulting from half neutralization of soluble carbonates (eqn. (2))

Various steps to be followed

a) A known volume of water sample is titrated against std. HCl using first phenolphthalein indicator till
end-point (P) and the titration is continued without break using methyl orange indicator till the end-
point (M).



10


Titration

Estimation of Alkalinity in water sample

Standard HCl Vs Water sample Indicator: 1. Phenolphthalein
2. Methyl Orange


S.No.
Volume
of water
sample (ml)
Burette Reading
Concordant value

Initial Phenolphthalein End
Point (P)
Methyl Orange End
Point (M)

1

2






CALCULATION

Hydroxide ion alkalinity
Volume of HCl (2P-M) = ???????ml

Strength of HCl = ???????? N

Volume of water sample = ???????...ml

Strength of water sample = Volume of HCl (2P-M) x Strength of HCl
Volume of water sample

=

? Hydroxide ion alkalinity in terms of
CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ??????.mg/l







11




b) From the magnitudes of the P & M, the nature of alkalinity can be arrived as follows:

(i) P = M => Presence of only OH
-

(ii) 2P = M => Presence of only CO 3
2-

(iii) P =0, M=0 => Presence of only HCO 3
-
(iv) 2P > M => Presence of OH
-
& CO 3
2-
(v) 2P < M => Presence of HCO 3
-
& CO 3
2-

(Mixture of OH
-
& HCO3
-
is not listed since they do not exist together and are considered equivalent to CO 3
2-
).

PROCEDURE
TITRATION
ESTIMATION OF ALKALINITY IN WATER SAMPLE

Exactly 20 ml of water sample is pipetted out into a clean conical flask. Few drops of phenolphthalein
indicator are added and titrated against a standardized HCl taken in the burette. The end point is the
disappearance of pink colour, which is noted as P. Few drops of methyl orange indicator is added to the same
solution. The solution turns to yellow. The titration is continued further by adding same HCl without break till the
end point is reached. The end point is the colour change from yellow to reddish orange.

The experiment is repeated to get concordant values. From the magnitudes of P & M values, the type of
alkalinity present in the water sample is inferred and the individual amounts are calculated and reported.










12


Carbonate ion alkalinity

Volume of HCl 2 (M ? P) = ??? ????????ml

Strength of HCl = ??.?????..???...N

Volume of water sample =........................................ml

Strength of water sample = Volume of HCl 2 (M ? P) x Strength of HCl
Volume of water sample

= ???????????.. N




? Carbonate ion alkalinity
in terms of CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ???????????mg/l

















13





RESULT

1) The type of alkalinity present in the water sample = -------------------------ions.

2) The individual amounts of alkalinity present in the water sample:
Hydroxide ion alkalinity

= ----------------- ppm
Carbonate ion alkalinity = ------------------ ppm
Bicarbonate ion alkalinity = ----------------- ppm





VIVA-VOCE


1. What is meant by alkalinity?
2. What are the ions responsible for alkalinity?
3. Why OH
-
and HCO 3
?
ions cannot exist together in water?
4. What are the ions responsible for alkalinity when 2P > M?
5. What is the pH range for both in acidic and basic solutions?
6. What is the colour of phenolphthalein in an acid and in an alkaline solution?
7. What is the purpose of using two indicators in same titration?
8. What are the possible combinations of ions for alkalinity?
9. How is the amount of alkalinity expressed?
10. What are the types of indicator used in this experiment?







14

SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II TITRATION III
Standardisation of
EDTA
(EDTA Vs Std
Hard water)
Determination of
total hardness
(Std EDTA Vs Hard
water sample)
Determination of
permanent hardness
(Std EDTA Vs Boiled
Hard water sample)

Burette solution

EDTA solution

EDTA solution

EDTA solution

Pipette solution

20ml Std. hard water

20 ml hard water sample

20ml boiled hard water sample

Indicator

2 drops of EBT

2 drops of EBT

2 drops of EBT

Additional soln.


Ammoniacal Buffer
solution (5ml)

Ammoniacal Buffer solution
(5ml)

Ammoniacal Buffer solution
(5ml)
End point Wine - red to Steel blue Wine - red to steel blue Wine - red to Steel blue




STANDARDISATION OF EDTA
Titration - I
Std. HARD WATER Vs EDTA Indicator: EBT

S. No.
Volume of std hard
water (ml)
Burette Reading Volume of
EDTA
(V 1) (ml)
Concordant value

Initial

Final



Volume of std .hard water taken = 20 ml
Volume of EDTA consumed (V 1) = --------------- ml
1 ml of std.hard water = 1mg of CaCO 3
20 ml of std hard water = 20 mg of CaCO 3

V 1 ml of EDTA solution containing 20 mg of CaCO 3
1 ml of EDTA solution = 20 / V 1 mg of CaCO 3
= -----------------------mg of CaCO 3


15

Expt. No. 2 DETERMINATION OF TOTAL, TEMPORARY AND
PERMANENT HARDNESS OF WATER

AIM
To estimate the amount of total, temporary & permanent hardness in the given sample of water.

PRINCIPLE
The estimation is based on the complexometric titration.

(i) Total hardness of water is estimated by titrating against EDTA using EBT indicator.
EBT+M ?[EBT-M] (unstable complex)
(EBT-M) (Unstable complex) +EDTA ? [EDTA-M] (stable complex) +EBT
EBT indicator forms wine- red colored complex with metal ions present in water. On addition of EDTA
metal ions preferably forms complexes with EDTA and steel blue EBT indicator is set free. Therefore
change of colour from wine- red to steel blue denotes the end point.

(ii) Temporary hardness is removed by boiling the water.
Ca (HCO 3) 2 ? CaCO 3 +CO 2 ?+H 2O
Mg (HCO 3) 2 ? Mg(OH) 2 +2CO 2 ?
The precipitate is filtered and the remaining permanent hardness is estimated using EDTA.

PROCEDURE

TITRATION ? I
STANDARDISATION OF EDTA

Pipette out 20ml of standard hard water into a 250ml conical flask. Add 5ml of buffer solution and 3
drops of eriochrome black T indictor. Titrate the solution with EDTA from the burette until the colour
changes from wine- red to steel blue at the end point. Repeat the titration for concordant values. Let the
titre value be V 1ml.


16


Titration-II
SAMPLE HARD WATER Vs Std EDTA Indicator: EBT

S.No. Volume of sample
hard water (ml)
Burette Reading Volume of
EDTA
(V 2) (ml)
Concordant value

Initial

Final




CALCULATION

Calculation of total hardness


Volume of EDTA consumed (V 2) = ------------------------- ml
1ml of EDTA = 20 / V 1 mg of CaCO 3
V 2 ml of EDTA = 20 / V 1 x V 2 mg of CaCO 3

( i.e), If 20ml of sample hard water contains 20 x V 2 mg of CaCO 3 / V 1

Then 1000ml of water sample = 20 x V 2 x 1000 / V 1 x 20 mg of CaCO 3

= 1000 x V 2 / V 1 mg of CaCO3

Total hardness of given water sample = ---------------------ppm









17



DETERMINATION OF TOTAL HARDNESS

Pipette out 20ml of sample hard water into a clean conical flask. Add 5ml of buffer solution and 4 -5
drops of Eriochrome black -T indicator. Titrate the wine - red coloured solution with EDTA from the burette until
the colour steel blue appears at the end point. Repeat the titration for concordant values. Let the titre value be
V 2ml.



DETERMINATION OF PERMANENT HARDNESS

Take 100ml of hard water sample in a 500ml beaker and boil gently for about 1hour. Cool, filter it into a
100ml standard flask and make the volume up to the mark. Take 20ml of this solution and proceed it in the same
way as in titration (I). The volume of EDTA consumed corresponds to the permanent hardness of the water
sample. Let the titre value be V 3ml. Temporary hardness is calculated by subtracting permanent hardness from
total hardness.





















18




DETERMINATION OF PERMANENT HARDNESS
BOILED SAMPLE WATER Vs Std. EDTA Indicator: EBT


S.No.
Volume of boiled
hard water (ml)
Burette Reading (ml) Volume of
EDTA
(ml)

Concordant value

Initial Final



CALCULATION OF PERMANENT HARDNESS


Volume of EDTA consumed V 3 = ---------------------ml

1ml of EDTA = 20 / V 1 mg of CaCO 3

V 3ml of EDTA = 20 / V 1 x V 3 mg of CaCO 3

(i.e) 20 ml of boiled sample hard water = 20 / V 1 x V 3 mg of CaCO 3

Then 1000ml of boiled water sample = 20 / V 1 x V 3 / 20 * 1000mg of CaCO 3

= 1000 x V 3 / V 1 mg of CaCO 3

permanent hardness of boiled water sample = -----------------ppm

Temporary hardness of the given water sample = Total hardness ? Permanent hardness

= ------------------ppm

19







RESULT

(i) Total hardness of the given sample water = -------------- ppm.
(ii) Permanent hardness of the given sample water = --------------- ppm.
(iii) Temporary hardness of the given sample water = ----------------ppm.







VIVA-VOCE

1. Define ? Hard water
2. What is the structure of EDTA?
3. How will you calculate temporary hardness?
4. What is the role of the buffer in EDTA titration?
5. What is the permissible limit of hardness in drinking water?
6. Name the hardness producing ions present in water.
7. Name two salts which are responsible for temporary hardness.
8. Why is CaCO 3 taken as the standard?
9. Write the expansion of EDTA.
10. What is meant by EBT?











20





SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II
Standardisation of
AgNO 3
Estimation of Chloride
Burette solution

AgNO 3 solution

Std. AgNO 3 solution

Pipette solution

20ml std KCl solution

20 ml water sample

Indicator

1ml K 2CrO 4

1ml K 2CrO 4


End point

yellow to reddish brown

yellow to reddish brown

Titration I
Std. AgNO3 Vs KCl Indicator: Potassium Chromate













CALCULATION

Volume of KCl (V 1) = ------- ml

Strength of KCl (N 1) = ------- N

Volume of Silver Nitrate (V 2) = -------- ml

Strength of Siver Nitrate V 1N 1
N 2 =
V 1

= --------------------- N

S.No.
Volume of KCl
(ml)
Burette Reading (ml)
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

21




Expt.No. 3 ESTIMATION OF CHLORIDE CONTENT IN WATER
(ARGENTOMETRIC METHOD)
AIM
To estimate the amount of chloride present in given water sample by Argentometric method (Mohr?s
method). You are provided with standard solution of NaCl of strength --------N and a approximately N/10 solution of
Silver nitrate.

PRINCIPLE
The Chloride ion in the form of NaCl, KCl, CaCl 2, MgCl 2 etc., present in the water sample can be estimated
by Argentometric method or known as Mohr?s method. It is an example for precipitation titration. The reaction
between std. Sodium chloride and Silver nitrate is given below.
AgNO 3 + NaCl ? AgCl ? + NaNO 3
The completion of reaction can be observed by employing potassium chromate as the indicator. The end
point is the colour change from yellow to reddish brown due to the following reaction.
2AgNO 3 + K 2CrO 4 ? Ag 2CrO 4 ? + 2KNO 3
Potassium chromate indicator will not be precipitated as silver chromate until all the chlorides in the solution
have been precipitated as AgCl Since a precipitation reaction takes place in preference, this reaction takes place
only at the end point.

PROCEDURE
TITRATION I: STANDARDISATION OF SILVER NITRATE
Pipette out 20ml of standard sodium or potassium chloride solution into a clean conical flask. Add 1ml of 5%
K 2CrO 4 indicator, as the solution turns yellow in colour. Titrate it against silver nitrate solution taken in the burette.
Observe the nearness of the end point through the formation of coagulated silver chloride precipitate at the bottom
of the flask. Now add the silver nitrate drop by drop until the solution gets a faint reddish brown tinge. Repeat the
titration for concordant value. Let the volume of silver nitrate be V 2ml.





22






TITRATION - II

Std AgNO3 Vs WATER SAMPLE Indicator: Potassium Chromate













CALCULATION

Volume of Silver Nitrate (V 3) = ------------ ml

Strength of Siver Nitrate (N 3) = ------------- N

Volume of Water sample (V 4) = -------------- ml

Strength of Water sample V 3 N 3
(N 4) =
V 4

= ----------------- N

Amount of Chloride ion present in 1000 ml of the water sample = Equivalent mass of HCl X 1000


= N 4 x 35.46 x 1000


= -----------------mg/l







S.No.
Volume of water
sample (ml)
Burette Reading
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

23





TITRATION - II
ESTIMATION OF CHLORIDE ION

Pipette out 40 ml of the given water sample into a clean conical flask.To this sample add 1ml of 5% K 2CrO 4
indicator and titrate it against the standardized silver nitrate solution taken in the burette and continue the titration
until the solution produces a reddish brown colour. Note down the end point and repeat the titration for
concordance. Let the volume be V 3ml.







RESULT

The amount of chloride ion present in the water sample = ----------------- mg/l.




VIVA-VOCE

1. Why is this method known as Argentometric method?
2.
What is the chemical reaction between AgNO 3 and Cl
-
ions present in water?

3.
What is the form of Chloride ion present in water?

4. What is the reaction between AgNO 3 and K 2CrO 4 ?
5. What is the name of the method used in this titration?
6. Name the link solution used in the determination.
7. Name the solution used to standardize AgNO 3.
8. What is the indicator used in the determination?
9. How will you calculate the amount of chloride ion in the given solution?
10. What is the colour change in the titration?




24




SHORT PROCEDURE


CONTENTS

TITRATION I

TITRATION II
Burette solution

Std Sodium Hydroxide

Std Sodium Hydroxide

Pipette solution

20 ml hydrochloric acid 20 ml hydrochloric acid
Additional solution


20 ml distilled water

20 ml distilled water


End point



Sudden increase in pH
pH gradual increase

Equivalent Weight of HCl = 36.5







ROUGH GRAPH FAIR GRAPH











pH
? pH/ ? V





Volume of NaOH
(ml)
Volume of NaOH
(ml)





25



Expt. No. 4 DETERMINATION OF STRENGTH OF HCl by pH METRY

AIM
To determine the strength of given HCl by pH metry. A standard solution of 0.1N NaOH is provided.

PRINCIPLE
The pH of a solution is related to H
+
ion concentration by the following formula.

. pH = -log [ H
+
]

pH of a solution is indirectly related to H
+
ion concentration. When NaOH is added slowly to HCl, H
+
ions
get neutralized by OH
-
ions. The pH increases slowly.

H
+
+ Cl
-
+ Na
+
+ OH
-
? Na
+
+ Cl
-
+H 2O

When all H
+
ions of HCl are neutralized at the end point, addition of NaOH causes high increase in pH
because of the addition of excess OH
-
ions.

MATERIALS REQUIRED
pH meter, Glass electrode, Burette, Pipette, Std.NaOH, approximately N/10 HCl .

PROCEDURE

The burette is washed with distilled water, rinsed with the given std. Sodium hydroxide and filled with the
same solution. Exactly 10ml of the given HCl solution is pipetted out into a clean beaker. It is then diluted to 50ml
with distilled water. A glass electrode is dipped into the solution and its terminals are connected to a pH meter.

26

TITRATION - I
S.No Volume of
NaOH (ml)
pH
1

2

3

4

5

6

7

8

9

10


TITRATION - II



CALCULATION

Volume of NaOH (V 1) = ------------------- ml ( titre value)
Strength of NaOH (N 1) = ------------------- N
Volume of HCl (V 2) = ------------------ml
Strength of HCl (N 2) = ------------------ N
N 2 = V 1 N 1 / V 2
Strength of HCl = -------------------- N
Amount of HCl present in 1000ml of the given solution = Strength x equivalent weight of HCl
= ------------------ X 36.5
= --------------------- g
S.No Volume of
NaOH (ml)
pH
11

12

13

14

15

16

17

18

19

20

S.No
Volume of
NaOH (ml)
pH ?pH ?V ?pH / ?V
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
27



Now NaOH is gradually added from the burette to HCl taken in the beaker. pH of the solution is noted for
each addition of NaOH. This process is continued until 5 readings are taken after the end point.
A fair titration is performed to find the exact end point.





RESULT

(i) Strength of the given HCl solution = ---------------- N
(ii) Amount of HCl present in a litre of the solution = ---------------- g


VIVA-VOCE

1. What is meant by pH?
2. What is the name of the reference electrode used ?
3. Why does pH value increase suddenly at the end point?
4. What is the indicator used in the titration?
5. What is the pH range of human blood?
6. What is the unit of pH?
7. How will you calculate the amount of HCl?
8. How is glass electrode represented?
9. Why is glass electrode known as ion selective electrode?
10. What is the chemical reaction involved in this titration?





28




SHORT PROCEDURE


CONTENTS
TITRATION
Burette solution

Std Sodium Hydroxide

Pipette solution

20 ml mixture of acid (HCl+ CH 3COOH)


Additional solution

20 ml distilled water


End point

Conductivity decreases-slowly increases-Sudden increase



Equivalent Weight of HCl = 36.5


Equivalent Weight of CH 3COOH = 60



MODEL GRAPH


Conductance
Volume of NaOH
Mixture of Acids






29




Expt. No. 5 CONDUCTOMETRIC TITRATION OF MIXTURE
OF ACIDS

AIM
To determine the amount of a strong acid and a weak acid present in the given solution.

PRINCIPLE

Solution of electrolytes conducts electricity due to the presence of ions. Since specific conductance of a
solution is proportional to the concentration of ions in it, conductance of the solution is measured during the titration.

HCl + NaOH ? NaCl + H 2O (I neutralization)

CH 3COOH + NaOH ? CH 3COONa + H 2O (II neutralization)

When a solution of HCl is treated with NaOH the fast moving hydrogen ions are progressively replaced by
slow moving sodium ions. As a result conductance of the solution decreases. This decrease will take place until the
first neutralisation point is reached. Further addition of alkali results in formation of sodium acetate.

Since sodium acetate is stronger than acetic acid conductivity slowly increases until all acetic acid is
completely neutralized.(II Neutralisation) This is due to the presence of fast moving OH
-
ions. Anymore addition of
alkali increases the conductance sharply.

PROCEDURE
The burette is filled with NaOH solution upto zero mark. The given unknown solution (mixture of a weak &
a strong acid) is transferred into a 100ml standard flask and made upto the mark with distilled water. 20ml of the
made up solution is pipetted out into a clean 100ml beaker. The solution is diluted to 20ml using distilled water. A
conductivity cell is dipped into the solution and the terminals are connected to a conductivity meter.
30


TITRATION


CALCULATION OF STRENGTH OF HCl
Volume of NaOH (V 1) = --------------- ml (titre value)
Strength of NaOH (N 1) = ---------------- N
Volume of HCl (V 2) = ------------ ml
Strength of HCl (N 2) = -------------- N

N 2 = V 1 N 1 / V 2
Strength of HCl = ---------------- N
CALCULATION OF STRENGTH OF CH3COOH
Volume of NaOH (V 1) = ------------ ml (titre value)
Strength of NaOH (N 1) = ------------ N
Volume of CH 3COOH (V 2) = ------------ ml
Strength of CH 3COOH (N 2) = ------------ N
N 2 = V 1 N 1 / V 2

Strength of CH 3COOH = ------------ N



S.No

Volume of NaOH
(ml)

Conductance (mho)

14

15

16

17
18
19
20

21
22
23
24
25
26

S.No

Volume of NaOH
(ml)

Conductance (mho)

1
2
3
4
5
6
7
8
9
10
11
12
13
31

The burette solution is added to the unknown solution in the beaker in 0.5 ml increments, the solution is
stirred using a glass rod, and the observed conductance values are read from the meter. The conductance values
show decrease in the initial values, then gradually increases and finally shows a steep increase. The titration hence
shows two end-points (i.e) I neutralization (weak acid) & II neutralization (strong acid).
The accurate end-point is obtained by plotting a graph between observed conductance Vs volume of
NaOH added.

RESULT
The strength of acids present in the given unknown solution are:
a) Strong acid = ---------------- N
b) Weak acid = -----------------N



VIVA-VOCE

1. What is weak acid?
2. How many end points are obtained from the graph? Comment two end points.
3. Why is the conductance increase in the first end point?
4. What mixture of acids used in this titration?
5. Write the neutralization reaction between CH 3COOH and NaOH.
6. What is the solution present in the conductivity cell?
7. What are strong and weak electrolytes?
8. Give an example for strong acid and weak acid.
9. What is the strong electrolyte of weak electrolyte?
10. Give an example for strong base.









32

SHORT PROCEDURE



















ROUGH GRAPH







EMF(mV)






Volume of Potassium dichromate (ml)

FAIR GRAPH









? E / ? V

Volume of Potassium dichromate (ml)




CONTENTS

TITRATION I

TITRATION II
Burette solution

Std Potassium dichromate

Std Potassium dichromate

Pipette solution

10 ml of FAS


10 ml of FAS



Additional
solution

20 ml distilled water+
10 ml of dil H 2SO 4


20 ml distilled water+
10 ml of dil H 2SO 4

End point

Sudden increase in EMF

EMF increases and decreases

Equivalent Weight of Ferrous ion = 55.85

33


Expt. No. 6 ESTIMATION OF FERROUS ION BY POTENTIOMETRIC
TITRATION

AIM
To estimate the amount of ferrous ion present in whole of the given solution potentiometrically. A standard
solution of potassium dichromate of strength -----------N is provided.

PRINCIPLE

Potentiometric titrations depend on measurement of emf between reference electrode and an indicator
electrode. When a solution of ferrous iron is titrated with a solution of potassium dichromate, the following redox
reaction takes place.

6Fe
2+
+ Cr 2O 7
2-
+ 14 H
+
? 6Fe
3+
+ 2Cr
3+
+ 7H 2O

During this titration Fe
2+
is converted in to Fe
3+
, whose concentration increases. At the end point, there
will be a sharp change due to sudden removal of all Fe
2+
ions.
The cell is set up by connecting this redox electrode with a calomel electrode as shown below:

Pt, Fe
2+
, Fe
3+
, II KCl , HgCl 2 (s), Hg

A graph between EMF measured against the volume of potassium dichromate added is drawn and the
end point is noted from the graph.

PROCEDURE

10ml of Ferrous solution is pipetted out into a 100 ml beaker. 10ml of dil.H 2SO 4 and 20ml of distilled water
are added. A platinum electrode and a calomel electrode are dipped into this solution and connected to the
potentiometer. Then 1ml of potassium dichromate is added to the solution and stirred well for 30 seconds. The
EMF is measured and the titration is continued by adding potassium dichromate in 1ml increments till five
measurements after the end point.



34


ROUGH TITRATION



S.No.

Volume of dichromate (ml)

EMF (mV)


1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.





35







A graph is drawn by plotting the emf against the volume of potassium dichromate and the end point range is
fixed.


About 20ml of Ferrous solution is pipetted out and the titration is continued by adding 0.1ml increaments of
potassium dichromate in the end point range. The emf is measured for each 0.1ml after stirring the solution well.


A graph is plotted between emf and the volume of potassium dichromate and also a first derivative graph is
plotted ( ? E/ ? V against vol. of K 2Cr 2O 7). The strength of Ferrous solution and the amount of Ferrous ion present are
calculated from the end point.



























36

FAIR TITRATION

S.No Volume of
Dichromate (ml)
Emf (mV) ?E ?V ?E/?V






















CALCULATION

Volume of Potassim dichromate (V 1) = -------------- ml
Normality of Potassium dichromate (N 1) = --------------- N
Volume of Ferrous sulphate (V 2) = --------------- ml
Normality of Ferrous sulphate (N 2) = --------------- N
Amount of Ferrous ion present in 1000ml of the solution = Normality X Equivalent weight of ferrous ion
= --------------- X 55.85 g

The amount of Ferrous ion present in the given solution = ----------------- g






37









RESULT

The amount of Ferrous ion present in the whole of the given solution = --------------- g.








VIVA-VOCE

1. What is EMF?
2. What is the basic principle of potentiometric titration?
3. Why does EMF increase during the titration?
4. Write the cell representation of the titration.
5. What is redox reaction?
6. What is the purpose of adding sulphuric acid?
7. What are the advantages of potentiometric titration?
8. How will you obtain the end point in the titration?
9. What is the name of the indicator electrode used in this titration?
10. What is the name of the reference electrode used?








38



SHORT PROCEDURE



CONTENTS

TITRATION
Burette solution

Sodium Hydroxide

Pipette solution

20 ml HCl


Additional solution

20 ml distilled water


End point

Decrease in conductance- increase in conductance

Equivalent Weight of HCl = 36.5
















Conductance

Volume of NaOH ( ml)









39


Expt.No. 7 CONDUCTOMETRIC TITRATION OF STRONG ACID
WITH STRONG BASE
AIM

To determine the strength of a strong acid by titrating a strong acid and strong base conductometrically. A
standard solution of NaOH of known strength ---------N is provided.

PRINCIPLE
Solution of electrolytes conducts electricity due to the presence of ions. The specific conductance of a
solution is proportional to the concentration of ions in it. The reaction between HCl and NaOH may be represented
as,
HCl +NaOH ? NaCl + H 2O

When a solution of hydrochloric acid is titrated with NaOH, the fast moving hydrogen ions are
progressively replaced by slow moving sodium ions. As a result conductance of the solution decreases, this
decrease in conductance will take place until the end point is reached. Further addition of alkali raises the
conductance sharply, as there is an excess of hydroxide ions.

A graph is drawn between volume of NaOH added and the conductance of solution. The exact end point
is intersection of the two lines.

PROCEDURE

The given HCl is made up in a 100ml standard flask. 10 ml of this solution is pipetted out in a beaker. The
burette is filled with standard sodium hydroxide upto the mark.

A conductivity cell is dipped into the beaker with HCl solution and connected to the terminals of the
conductivity bridge. About 1ml of STD NaOH is added and stirred well for 30 seconds. The conductance is
measured and the titration is continued till five measurements after the endpoint. A graph is plotted for the
conductance values against the volume of NaOH and the endpoint range is fixed.

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?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





3


PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)
1. Fundamentals
To provide students with a solid foundation in Mathematics, Science and fundamentals of engineering,
enabling them to apply, to find solutions for engineering problems and use this knowledge to acquire higher
education
2. Core Competence
To train the students in chemistry practicals so that they apply their knowledge and training to compare,
and to analyze various engineering industrial problems to find solutions
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice this enables
them to find solutions for the real time problems in industry, and to design products
4. Professionalism
To inculcate professional and effective communication skills, leadership qualities and team spirit in the
students to make them multi-faceted personalities and develop their ability to relate engineering issues to
broader social context
5. Lifelong Learning/Ethics
To demonstrate and practice ethical and professional responsibilities in the industry and society in the
large, through commitment and lifelong learning needed for successful professional career






4


PROGRAMME OUTCOMES (POs)
To demonstrate and apply knowledge of Mathematics, Science and engineering fundamentals in the following
experiments.
1 .To estimate HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. To determine total, temporary & permanent hardness of water by EDTA method.
3. To determine DO content of water sample by Winkler?s method.
4. To determine chloride content of water sample by Argentometric method.
5. To estimate copper content of the given solution by Iodometry.
6. To determine strength of given hydrochloric acid using pH meter.
7. To determine strength of acids in a mixture of acids using conductivity meter.
8. To determine iron content of the given solution using potentiometer.
9. To estimate iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. To estimate sodium and potassium present in water using flame photometer.
11. To determine molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. To determine Pseudo first order kinetics ? ester hydrolysis.
13. To determine Corrosion experiment ? weight loss method.
14. To estimate CMC.
15. To estimate Phase change in a solid.
16. To determine strength of strong acid vs strong base using conductivity meter.











5

BS8161 - CHEMISTRY LABORATORY
SYLLABUS


? To make the student to acquire practical skills in the determination of water quality
parameters through volumetric and instrumental analysis.

? ???? ??? ???? ?? ???? ? ? ?To acquaint the students with the determination of molecular weight of a polymer by
viscometery.

LIST OF EXPERIMENTS:
1. Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. Determination of total, temporary & permanent hardness of water by EDTA method.
3. Determination of DO content of water sample by Winkler?s method.
4. Determination of chloride content of water sample by Argentometric method.
5. Estimation of copper content of the given solution by Iodometry.
6. Determination of strength of given hydrochloric acid using pH meter.
7. Determination of strength of acids in a mixture of acids using conductivity meter.
8. Estimation of iron content of the given solution using potentiometer.
9. Estimation of iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. Estimation of sodium and potassium present in water using flame photometer.
11. Determination of molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. Pseudo first order kinetics ? ester hydrolysis.
13. Corrosion experiment ? weight loss method.
14. Determination of CMC.
15. Phase change in a solid.
16. Conductometric titration of strong acid vs strong base.




? The students will be outfitted with hands-on knowledge in the quantitative chemical
analysis of water quality related parameters.
COURSE OBJECTIVES
COURSE OUTCOMES
6


INDEX [ SEMESTER ? I ]


S.No.



Date


Experiment

Date of
submission



Mark


Signature

1.

Estimation of HCl using Na 2CO 3 as
primary standard and Determination of
alkalinity in water sample.



2.


Determination of total, temporary &
permanent hardness of water by EDTA
method.



3.


Determination of chloride content of water
sample by argentometric method.



4.


Determination of strength of given
hydrochloric acid using pH meter.



5.


Determination of strength of acids in a
mixture of acids using conductivity meter.



6.


Estimation of iron content of the given
solution using potentiometer.



7.





Conductometric titration of strong acid Vs
strong base.



8.



Estimation of copper content of the given
solution by Iodometry


9.
Estimation of sodium and potassium
present in water using flame photometer




7




CONTENTS


S.No.


NAME OF EXPERIMENT

PAGE
No.
SEMESTER - I
1.
Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in
water sample.
09
2. Determination of total, temporary & permanent hardness of water by EDTA method. 15
3. Determination of chloride content of water sample by Argentometric method. 21
4. Determination of strength of given hydrochloric acid using pH meter. 25
5. Determination of strength of acids in a mixture of acids using conductivity meter. 29
6. Estimation of iron content of the given solution using potentiometer. 33
7. Conductometric titration of strong acid Vs strong base.

39


42

8


Estimation of copper content of the given solution by Iodometry 43
9 Estimation of sodium and potassium present in water using flame photometer 47






8



SHORT PROCEDURE:

CONTENTS
TITRATION
Estimation of alkalinity in water sample
(Std HCl Vs water sample)

Burette solution

Std. HCl


Pipette solution

Water sample


Indicator


(i) Phenolphthalein
(ii) Methyl orange


End point

(i) Disappearance of pink colour
(ii) Appearance of reddish orange colour






Relationship
between P &M
Nature of alkalinity
Amount of individual
alkalinities
OH
-
HCO 3
-


CO 3
2-

P = M

only OH
-

P or M

?
0.0

0.0


2P = M

only CO 3
2-


2P or M


0.0


0.0


?

P =0, M?0

only HCO 3
-



M



0.0



?

0.0


2P > M


OH
-
&CO 3
2-


OH
-
= 2P-M
CO 3
2-
= 2(M-P)


?

0.0

?

P < ? M




HCO 3
-
&CO 3
2-


HCO 3
-
= M-2P
CO 3
2-
= 2P

0.0 ? ?




9





Expt. No. 1 DETERMINATION OF ALKALINITY IN WATER
AIM
To determine the type and amounts of alkalinity in the given water sample. A standard solution of Na 2CO 3
of strength ____N is given.

PRINCIPLE
Alkalinity in water is due to the presence of soluble hydroxides, bicarbonates and carbonates.
Determination of various types and amounts of alkalinity is easily carried out by titration with standard HCl
employing the indicators phenolphthalein and methyl orange independently or in succession.

The following reactions occur when different types of alkalinity are neutralized with acid.

OH
?
+ H
+
? H 2O completed at pH 8.2-9.0 ----- (1)

CO 3
2 ?
+ H
+
? HCO 3
?
----- (2)

HCO 3
?
+ H
+
? (H 2CO 3) ? H 2O + CO 2, completed at pH 4.2-5.5 ----- (3)

Neutralisation (1) & (2) will be notified by phenolphthalein end-point while all the three will be

accounted by
methyl orange end-point. Bicarbonate in eqn. (3) may be due to the existence of soluble free bicarbonate salts and
bicarbonates resulting from half neutralization of soluble carbonates (eqn. (2))

Various steps to be followed

a) A known volume of water sample is titrated against std. HCl using first phenolphthalein indicator till
end-point (P) and the titration is continued without break using methyl orange indicator till the end-
point (M).



10


Titration

Estimation of Alkalinity in water sample

Standard HCl Vs Water sample Indicator: 1. Phenolphthalein
2. Methyl Orange


S.No.
Volume
of water
sample (ml)
Burette Reading
Concordant value

Initial Phenolphthalein End
Point (P)
Methyl Orange End
Point (M)

1

2






CALCULATION

Hydroxide ion alkalinity
Volume of HCl (2P-M) = ???????ml

Strength of HCl = ???????? N

Volume of water sample = ???????...ml

Strength of water sample = Volume of HCl (2P-M) x Strength of HCl
Volume of water sample

=

? Hydroxide ion alkalinity in terms of
CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ??????.mg/l







11




b) From the magnitudes of the P & M, the nature of alkalinity can be arrived as follows:

(i) P = M => Presence of only OH
-

(ii) 2P = M => Presence of only CO 3
2-

(iii) P =0, M=0 => Presence of only HCO 3
-
(iv) 2P > M => Presence of OH
-
& CO 3
2-
(v) 2P < M => Presence of HCO 3
-
& CO 3
2-

(Mixture of OH
-
& HCO3
-
is not listed since they do not exist together and are considered equivalent to CO 3
2-
).

PROCEDURE
TITRATION
ESTIMATION OF ALKALINITY IN WATER SAMPLE

Exactly 20 ml of water sample is pipetted out into a clean conical flask. Few drops of phenolphthalein
indicator are added and titrated against a standardized HCl taken in the burette. The end point is the
disappearance of pink colour, which is noted as P. Few drops of methyl orange indicator is added to the same
solution. The solution turns to yellow. The titration is continued further by adding same HCl without break till the
end point is reached. The end point is the colour change from yellow to reddish orange.

The experiment is repeated to get concordant values. From the magnitudes of P & M values, the type of
alkalinity present in the water sample is inferred and the individual amounts are calculated and reported.










12


Carbonate ion alkalinity

Volume of HCl 2 (M ? P) = ??? ????????ml

Strength of HCl = ??.?????..???...N

Volume of water sample =........................................ml

Strength of water sample = Volume of HCl 2 (M ? P) x Strength of HCl
Volume of water sample

= ???????????.. N




? Carbonate ion alkalinity
in terms of CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ???????????mg/l

















13





RESULT

1) The type of alkalinity present in the water sample = -------------------------ions.

2) The individual amounts of alkalinity present in the water sample:
Hydroxide ion alkalinity

= ----------------- ppm
Carbonate ion alkalinity = ------------------ ppm
Bicarbonate ion alkalinity = ----------------- ppm





VIVA-VOCE


1. What is meant by alkalinity?
2. What are the ions responsible for alkalinity?
3. Why OH
-
and HCO 3
?
ions cannot exist together in water?
4. What are the ions responsible for alkalinity when 2P > M?
5. What is the pH range for both in acidic and basic solutions?
6. What is the colour of phenolphthalein in an acid and in an alkaline solution?
7. What is the purpose of using two indicators in same titration?
8. What are the possible combinations of ions for alkalinity?
9. How is the amount of alkalinity expressed?
10. What are the types of indicator used in this experiment?







14

SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II TITRATION III
Standardisation of
EDTA
(EDTA Vs Std
Hard water)
Determination of
total hardness
(Std EDTA Vs Hard
water sample)
Determination of
permanent hardness
(Std EDTA Vs Boiled
Hard water sample)

Burette solution

EDTA solution

EDTA solution

EDTA solution

Pipette solution

20ml Std. hard water

20 ml hard water sample

20ml boiled hard water sample

Indicator

2 drops of EBT

2 drops of EBT

2 drops of EBT

Additional soln.


Ammoniacal Buffer
solution (5ml)

Ammoniacal Buffer solution
(5ml)

Ammoniacal Buffer solution
(5ml)
End point Wine - red to Steel blue Wine - red to steel blue Wine - red to Steel blue




STANDARDISATION OF EDTA
Titration - I
Std. HARD WATER Vs EDTA Indicator: EBT

S. No.
Volume of std hard
water (ml)
Burette Reading Volume of
EDTA
(V 1) (ml)
Concordant value

Initial

Final



Volume of std .hard water taken = 20 ml
Volume of EDTA consumed (V 1) = --------------- ml
1 ml of std.hard water = 1mg of CaCO 3
20 ml of std hard water = 20 mg of CaCO 3

V 1 ml of EDTA solution containing 20 mg of CaCO 3
1 ml of EDTA solution = 20 / V 1 mg of CaCO 3
= -----------------------mg of CaCO 3


15

Expt. No. 2 DETERMINATION OF TOTAL, TEMPORARY AND
PERMANENT HARDNESS OF WATER

AIM
To estimate the amount of total, temporary & permanent hardness in the given sample of water.

PRINCIPLE
The estimation is based on the complexometric titration.

(i) Total hardness of water is estimated by titrating against EDTA using EBT indicator.
EBT+M ?[EBT-M] (unstable complex)
(EBT-M) (Unstable complex) +EDTA ? [EDTA-M] (stable complex) +EBT
EBT indicator forms wine- red colored complex with metal ions present in water. On addition of EDTA
metal ions preferably forms complexes with EDTA and steel blue EBT indicator is set free. Therefore
change of colour from wine- red to steel blue denotes the end point.

(ii) Temporary hardness is removed by boiling the water.
Ca (HCO 3) 2 ? CaCO 3 +CO 2 ?+H 2O
Mg (HCO 3) 2 ? Mg(OH) 2 +2CO 2 ?
The precipitate is filtered and the remaining permanent hardness is estimated using EDTA.

PROCEDURE

TITRATION ? I
STANDARDISATION OF EDTA

Pipette out 20ml of standard hard water into a 250ml conical flask. Add 5ml of buffer solution and 3
drops of eriochrome black T indictor. Titrate the solution with EDTA from the burette until the colour
changes from wine- red to steel blue at the end point. Repeat the titration for concordant values. Let the
titre value be V 1ml.


16


Titration-II
SAMPLE HARD WATER Vs Std EDTA Indicator: EBT

S.No. Volume of sample
hard water (ml)
Burette Reading Volume of
EDTA
(V 2) (ml)
Concordant value

Initial

Final




CALCULATION

Calculation of total hardness


Volume of EDTA consumed (V 2) = ------------------------- ml
1ml of EDTA = 20 / V 1 mg of CaCO 3
V 2 ml of EDTA = 20 / V 1 x V 2 mg of CaCO 3

( i.e), If 20ml of sample hard water contains 20 x V 2 mg of CaCO 3 / V 1

Then 1000ml of water sample = 20 x V 2 x 1000 / V 1 x 20 mg of CaCO 3

= 1000 x V 2 / V 1 mg of CaCO3

Total hardness of given water sample = ---------------------ppm









17



DETERMINATION OF TOTAL HARDNESS

Pipette out 20ml of sample hard water into a clean conical flask. Add 5ml of buffer solution and 4 -5
drops of Eriochrome black -T indicator. Titrate the wine - red coloured solution with EDTA from the burette until
the colour steel blue appears at the end point. Repeat the titration for concordant values. Let the titre value be
V 2ml.



DETERMINATION OF PERMANENT HARDNESS

Take 100ml of hard water sample in a 500ml beaker and boil gently for about 1hour. Cool, filter it into a
100ml standard flask and make the volume up to the mark. Take 20ml of this solution and proceed it in the same
way as in titration (I). The volume of EDTA consumed corresponds to the permanent hardness of the water
sample. Let the titre value be V 3ml. Temporary hardness is calculated by subtracting permanent hardness from
total hardness.





















18




DETERMINATION OF PERMANENT HARDNESS
BOILED SAMPLE WATER Vs Std. EDTA Indicator: EBT


S.No.
Volume of boiled
hard water (ml)
Burette Reading (ml) Volume of
EDTA
(ml)

Concordant value

Initial Final



CALCULATION OF PERMANENT HARDNESS


Volume of EDTA consumed V 3 = ---------------------ml

1ml of EDTA = 20 / V 1 mg of CaCO 3

V 3ml of EDTA = 20 / V 1 x V 3 mg of CaCO 3

(i.e) 20 ml of boiled sample hard water = 20 / V 1 x V 3 mg of CaCO 3

Then 1000ml of boiled water sample = 20 / V 1 x V 3 / 20 * 1000mg of CaCO 3

= 1000 x V 3 / V 1 mg of CaCO 3

permanent hardness of boiled water sample = -----------------ppm

Temporary hardness of the given water sample = Total hardness ? Permanent hardness

= ------------------ppm

19







RESULT

(i) Total hardness of the given sample water = -------------- ppm.
(ii) Permanent hardness of the given sample water = --------------- ppm.
(iii) Temporary hardness of the given sample water = ----------------ppm.







VIVA-VOCE

1. Define ? Hard water
2. What is the structure of EDTA?
3. How will you calculate temporary hardness?
4. What is the role of the buffer in EDTA titration?
5. What is the permissible limit of hardness in drinking water?
6. Name the hardness producing ions present in water.
7. Name two salts which are responsible for temporary hardness.
8. Why is CaCO 3 taken as the standard?
9. Write the expansion of EDTA.
10. What is meant by EBT?











20





SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II
Standardisation of
AgNO 3
Estimation of Chloride
Burette solution

AgNO 3 solution

Std. AgNO 3 solution

Pipette solution

20ml std KCl solution

20 ml water sample

Indicator

1ml K 2CrO 4

1ml K 2CrO 4


End point

yellow to reddish brown

yellow to reddish brown

Titration I
Std. AgNO3 Vs KCl Indicator: Potassium Chromate













CALCULATION

Volume of KCl (V 1) = ------- ml

Strength of KCl (N 1) = ------- N

Volume of Silver Nitrate (V 2) = -------- ml

Strength of Siver Nitrate V 1N 1
N 2 =
V 1

= --------------------- N

S.No.
Volume of KCl
(ml)
Burette Reading (ml)
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

21




Expt.No. 3 ESTIMATION OF CHLORIDE CONTENT IN WATER
(ARGENTOMETRIC METHOD)
AIM
To estimate the amount of chloride present in given water sample by Argentometric method (Mohr?s
method). You are provided with standard solution of NaCl of strength --------N and a approximately N/10 solution of
Silver nitrate.

PRINCIPLE
The Chloride ion in the form of NaCl, KCl, CaCl 2, MgCl 2 etc., present in the water sample can be estimated
by Argentometric method or known as Mohr?s method. It is an example for precipitation titration. The reaction
between std. Sodium chloride and Silver nitrate is given below.
AgNO 3 + NaCl ? AgCl ? + NaNO 3
The completion of reaction can be observed by employing potassium chromate as the indicator. The end
point is the colour change from yellow to reddish brown due to the following reaction.
2AgNO 3 + K 2CrO 4 ? Ag 2CrO 4 ? + 2KNO 3
Potassium chromate indicator will not be precipitated as silver chromate until all the chlorides in the solution
have been precipitated as AgCl Since a precipitation reaction takes place in preference, this reaction takes place
only at the end point.

PROCEDURE
TITRATION I: STANDARDISATION OF SILVER NITRATE
Pipette out 20ml of standard sodium or potassium chloride solution into a clean conical flask. Add 1ml of 5%
K 2CrO 4 indicator, as the solution turns yellow in colour. Titrate it against silver nitrate solution taken in the burette.
Observe the nearness of the end point through the formation of coagulated silver chloride precipitate at the bottom
of the flask. Now add the silver nitrate drop by drop until the solution gets a faint reddish brown tinge. Repeat the
titration for concordant value. Let the volume of silver nitrate be V 2ml.





22






TITRATION - II

Std AgNO3 Vs WATER SAMPLE Indicator: Potassium Chromate













CALCULATION

Volume of Silver Nitrate (V 3) = ------------ ml

Strength of Siver Nitrate (N 3) = ------------- N

Volume of Water sample (V 4) = -------------- ml

Strength of Water sample V 3 N 3
(N 4) =
V 4

= ----------------- N

Amount of Chloride ion present in 1000 ml of the water sample = Equivalent mass of HCl X 1000


= N 4 x 35.46 x 1000


= -----------------mg/l







S.No.
Volume of water
sample (ml)
Burette Reading
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

23





TITRATION - II
ESTIMATION OF CHLORIDE ION

Pipette out 40 ml of the given water sample into a clean conical flask.To this sample add 1ml of 5% K 2CrO 4
indicator and titrate it against the standardized silver nitrate solution taken in the burette and continue the titration
until the solution produces a reddish brown colour. Note down the end point and repeat the titration for
concordance. Let the volume be V 3ml.







RESULT

The amount of chloride ion present in the water sample = ----------------- mg/l.




VIVA-VOCE

1. Why is this method known as Argentometric method?
2.
What is the chemical reaction between AgNO 3 and Cl
-
ions present in water?

3.
What is the form of Chloride ion present in water?

4. What is the reaction between AgNO 3 and K 2CrO 4 ?
5. What is the name of the method used in this titration?
6. Name the link solution used in the determination.
7. Name the solution used to standardize AgNO 3.
8. What is the indicator used in the determination?
9. How will you calculate the amount of chloride ion in the given solution?
10. What is the colour change in the titration?




24




SHORT PROCEDURE


CONTENTS

TITRATION I

TITRATION II
Burette solution

Std Sodium Hydroxide

Std Sodium Hydroxide

Pipette solution

20 ml hydrochloric acid 20 ml hydrochloric acid
Additional solution


20 ml distilled water

20 ml distilled water


End point



Sudden increase in pH
pH gradual increase

Equivalent Weight of HCl = 36.5







ROUGH GRAPH FAIR GRAPH











pH
? pH/ ? V





Volume of NaOH
(ml)
Volume of NaOH
(ml)





25



Expt. No. 4 DETERMINATION OF STRENGTH OF HCl by pH METRY

AIM
To determine the strength of given HCl by pH metry. A standard solution of 0.1N NaOH is provided.

PRINCIPLE
The pH of a solution is related to H
+
ion concentration by the following formula.

. pH = -log [ H
+
]

pH of a solution is indirectly related to H
+
ion concentration. When NaOH is added slowly to HCl, H
+
ions
get neutralized by OH
-
ions. The pH increases slowly.

H
+
+ Cl
-
+ Na
+
+ OH
-
? Na
+
+ Cl
-
+H 2O

When all H
+
ions of HCl are neutralized at the end point, addition of NaOH causes high increase in pH
because of the addition of excess OH
-
ions.

MATERIALS REQUIRED
pH meter, Glass electrode, Burette, Pipette, Std.NaOH, approximately N/10 HCl .

PROCEDURE

The burette is washed with distilled water, rinsed with the given std. Sodium hydroxide and filled with the
same solution. Exactly 10ml of the given HCl solution is pipetted out into a clean beaker. It is then diluted to 50ml
with distilled water. A glass electrode is dipped into the solution and its terminals are connected to a pH meter.

26

TITRATION - I
S.No Volume of
NaOH (ml)
pH
1

2

3

4

5

6

7

8

9

10


TITRATION - II



CALCULATION

Volume of NaOH (V 1) = ------------------- ml ( titre value)
Strength of NaOH (N 1) = ------------------- N
Volume of HCl (V 2) = ------------------ml
Strength of HCl (N 2) = ------------------ N
N 2 = V 1 N 1 / V 2
Strength of HCl = -------------------- N
Amount of HCl present in 1000ml of the given solution = Strength x equivalent weight of HCl
= ------------------ X 36.5
= --------------------- g
S.No Volume of
NaOH (ml)
pH
11

12

13

14

15

16

17

18

19

20

S.No
Volume of
NaOH (ml)
pH ?pH ?V ?pH / ?V
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
27



Now NaOH is gradually added from the burette to HCl taken in the beaker. pH of the solution is noted for
each addition of NaOH. This process is continued until 5 readings are taken after the end point.
A fair titration is performed to find the exact end point.





RESULT

(i) Strength of the given HCl solution = ---------------- N
(ii) Amount of HCl present in a litre of the solution = ---------------- g


VIVA-VOCE

1. What is meant by pH?
2. What is the name of the reference electrode used ?
3. Why does pH value increase suddenly at the end point?
4. What is the indicator used in the titration?
5. What is the pH range of human blood?
6. What is the unit of pH?
7. How will you calculate the amount of HCl?
8. How is glass electrode represented?
9. Why is glass electrode known as ion selective electrode?
10. What is the chemical reaction involved in this titration?





28




SHORT PROCEDURE


CONTENTS
TITRATION
Burette solution

Std Sodium Hydroxide

Pipette solution

20 ml mixture of acid (HCl+ CH 3COOH)


Additional solution

20 ml distilled water


End point

Conductivity decreases-slowly increases-Sudden increase



Equivalent Weight of HCl = 36.5


Equivalent Weight of CH 3COOH = 60



MODEL GRAPH


Conductance
Volume of NaOH
Mixture of Acids






29




Expt. No. 5 CONDUCTOMETRIC TITRATION OF MIXTURE
OF ACIDS

AIM
To determine the amount of a strong acid and a weak acid present in the given solution.

PRINCIPLE

Solution of electrolytes conducts electricity due to the presence of ions. Since specific conductance of a
solution is proportional to the concentration of ions in it, conductance of the solution is measured during the titration.

HCl + NaOH ? NaCl + H 2O (I neutralization)

CH 3COOH + NaOH ? CH 3COONa + H 2O (II neutralization)

When a solution of HCl is treated with NaOH the fast moving hydrogen ions are progressively replaced by
slow moving sodium ions. As a result conductance of the solution decreases. This decrease will take place until the
first neutralisation point is reached. Further addition of alkali results in formation of sodium acetate.

Since sodium acetate is stronger than acetic acid conductivity slowly increases until all acetic acid is
completely neutralized.(II Neutralisation) This is due to the presence of fast moving OH
-
ions. Anymore addition of
alkali increases the conductance sharply.

PROCEDURE
The burette is filled with NaOH solution upto zero mark. The given unknown solution (mixture of a weak &
a strong acid) is transferred into a 100ml standard flask and made upto the mark with distilled water. 20ml of the
made up solution is pipetted out into a clean 100ml beaker. The solution is diluted to 20ml using distilled water. A
conductivity cell is dipped into the solution and the terminals are connected to a conductivity meter.
30


TITRATION


CALCULATION OF STRENGTH OF HCl
Volume of NaOH (V 1) = --------------- ml (titre value)
Strength of NaOH (N 1) = ---------------- N
Volume of HCl (V 2) = ------------ ml
Strength of HCl (N 2) = -------------- N

N 2 = V 1 N 1 / V 2
Strength of HCl = ---------------- N
CALCULATION OF STRENGTH OF CH3COOH
Volume of NaOH (V 1) = ------------ ml (titre value)
Strength of NaOH (N 1) = ------------ N
Volume of CH 3COOH (V 2) = ------------ ml
Strength of CH 3COOH (N 2) = ------------ N
N 2 = V 1 N 1 / V 2

Strength of CH 3COOH = ------------ N



S.No

Volume of NaOH
(ml)

Conductance (mho)

14

15

16

17
18
19
20

21
22
23
24
25
26

S.No

Volume of NaOH
(ml)

Conductance (mho)

1
2
3
4
5
6
7
8
9
10
11
12
13
31

The burette solution is added to the unknown solution in the beaker in 0.5 ml increments, the solution is
stirred using a glass rod, and the observed conductance values are read from the meter. The conductance values
show decrease in the initial values, then gradually increases and finally shows a steep increase. The titration hence
shows two end-points (i.e) I neutralization (weak acid) & II neutralization (strong acid).
The accurate end-point is obtained by plotting a graph between observed conductance Vs volume of
NaOH added.

RESULT
The strength of acids present in the given unknown solution are:
a) Strong acid = ---------------- N
b) Weak acid = -----------------N



VIVA-VOCE

1. What is weak acid?
2. How many end points are obtained from the graph? Comment two end points.
3. Why is the conductance increase in the first end point?
4. What mixture of acids used in this titration?
5. Write the neutralization reaction between CH 3COOH and NaOH.
6. What is the solution present in the conductivity cell?
7. What are strong and weak electrolytes?
8. Give an example for strong acid and weak acid.
9. What is the strong electrolyte of weak electrolyte?
10. Give an example for strong base.









32

SHORT PROCEDURE



















ROUGH GRAPH







EMF(mV)






Volume of Potassium dichromate (ml)

FAIR GRAPH









? E / ? V

Volume of Potassium dichromate (ml)




CONTENTS

TITRATION I

TITRATION II
Burette solution

Std Potassium dichromate

Std Potassium dichromate

Pipette solution

10 ml of FAS


10 ml of FAS



Additional
solution

20 ml distilled water+
10 ml of dil H 2SO 4


20 ml distilled water+
10 ml of dil H 2SO 4

End point

Sudden increase in EMF

EMF increases and decreases

Equivalent Weight of Ferrous ion = 55.85

33


Expt. No. 6 ESTIMATION OF FERROUS ION BY POTENTIOMETRIC
TITRATION

AIM
To estimate the amount of ferrous ion present in whole of the given solution potentiometrically. A standard
solution of potassium dichromate of strength -----------N is provided.

PRINCIPLE

Potentiometric titrations depend on measurement of emf between reference electrode and an indicator
electrode. When a solution of ferrous iron is titrated with a solution of potassium dichromate, the following redox
reaction takes place.

6Fe
2+
+ Cr 2O 7
2-
+ 14 H
+
? 6Fe
3+
+ 2Cr
3+
+ 7H 2O

During this titration Fe
2+
is converted in to Fe
3+
, whose concentration increases. At the end point, there
will be a sharp change due to sudden removal of all Fe
2+
ions.
The cell is set up by connecting this redox electrode with a calomel electrode as shown below:

Pt, Fe
2+
, Fe
3+
, II KCl , HgCl 2 (s), Hg

A graph between EMF measured against the volume of potassium dichromate added is drawn and the
end point is noted from the graph.

PROCEDURE

10ml of Ferrous solution is pipetted out into a 100 ml beaker. 10ml of dil.H 2SO 4 and 20ml of distilled water
are added. A platinum electrode and a calomel electrode are dipped into this solution and connected to the
potentiometer. Then 1ml of potassium dichromate is added to the solution and stirred well for 30 seconds. The
EMF is measured and the titration is continued by adding potassium dichromate in 1ml increments till five
measurements after the end point.



34


ROUGH TITRATION



S.No.

Volume of dichromate (ml)

EMF (mV)


1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.





35







A graph is drawn by plotting the emf against the volume of potassium dichromate and the end point range is
fixed.


About 20ml of Ferrous solution is pipetted out and the titration is continued by adding 0.1ml increaments of
potassium dichromate in the end point range. The emf is measured for each 0.1ml after stirring the solution well.


A graph is plotted between emf and the volume of potassium dichromate and also a first derivative graph is
plotted ( ? E/ ? V against vol. of K 2Cr 2O 7). The strength of Ferrous solution and the amount of Ferrous ion present are
calculated from the end point.



























36

FAIR TITRATION

S.No Volume of
Dichromate (ml)
Emf (mV) ?E ?V ?E/?V






















CALCULATION

Volume of Potassim dichromate (V 1) = -------------- ml
Normality of Potassium dichromate (N 1) = --------------- N
Volume of Ferrous sulphate (V 2) = --------------- ml
Normality of Ferrous sulphate (N 2) = --------------- N
Amount of Ferrous ion present in 1000ml of the solution = Normality X Equivalent weight of ferrous ion
= --------------- X 55.85 g

The amount of Ferrous ion present in the given solution = ----------------- g






37









RESULT

The amount of Ferrous ion present in the whole of the given solution = --------------- g.








VIVA-VOCE

1. What is EMF?
2. What is the basic principle of potentiometric titration?
3. Why does EMF increase during the titration?
4. Write the cell representation of the titration.
5. What is redox reaction?
6. What is the purpose of adding sulphuric acid?
7. What are the advantages of potentiometric titration?
8. How will you obtain the end point in the titration?
9. What is the name of the indicator electrode used in this titration?
10. What is the name of the reference electrode used?








38



SHORT PROCEDURE



CONTENTS

TITRATION
Burette solution

Sodium Hydroxide

Pipette solution

20 ml HCl


Additional solution

20 ml distilled water


End point

Decrease in conductance- increase in conductance

Equivalent Weight of HCl = 36.5
















Conductance

Volume of NaOH ( ml)









39


Expt.No. 7 CONDUCTOMETRIC TITRATION OF STRONG ACID
WITH STRONG BASE
AIM

To determine the strength of a strong acid by titrating a strong acid and strong base conductometrically. A
standard solution of NaOH of known strength ---------N is provided.

PRINCIPLE
Solution of electrolytes conducts electricity due to the presence of ions. The specific conductance of a
solution is proportional to the concentration of ions in it. The reaction between HCl and NaOH may be represented
as,
HCl +NaOH ? NaCl + H 2O

When a solution of hydrochloric acid is titrated with NaOH, the fast moving hydrogen ions are
progressively replaced by slow moving sodium ions. As a result conductance of the solution decreases, this
decrease in conductance will take place until the end point is reached. Further addition of alkali raises the
conductance sharply, as there is an excess of hydroxide ions.

A graph is drawn between volume of NaOH added and the conductance of solution. The exact end point
is intersection of the two lines.

PROCEDURE

The given HCl is made up in a 100ml standard flask. 10 ml of this solution is pipetted out in a beaker. The
burette is filled with standard sodium hydroxide upto the mark.

A conductivity cell is dipped into the beaker with HCl solution and connected to the terminals of the
conductivity bridge. About 1ml of STD NaOH is added and stirred well for 30 seconds. The conductance is
measured and the titration is continued till five measurements after the endpoint. A graph is plotted for the
conductance values against the volume of NaOH and the endpoint range is fixed.

40


TABLE



CALCULATION
Volume of Sodium Hydroxide (V 1) = ------------- ml
Normality of Sodium Hydroxide (N 1) = ------------- N
Volume of Strong acid (V 2) = ------------- ml
Normality of Strong acid (N 2) = V 1 N 1
V 2

The strength of the given strong acid = ------------- N




S.NO
Volume of NaOH
(ml)
Conductance
(mho)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
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?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





3


PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)
1. Fundamentals
To provide students with a solid foundation in Mathematics, Science and fundamentals of engineering,
enabling them to apply, to find solutions for engineering problems and use this knowledge to acquire higher
education
2. Core Competence
To train the students in chemistry practicals so that they apply their knowledge and training to compare,
and to analyze various engineering industrial problems to find solutions
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice this enables
them to find solutions for the real time problems in industry, and to design products
4. Professionalism
To inculcate professional and effective communication skills, leadership qualities and team spirit in the
students to make them multi-faceted personalities and develop their ability to relate engineering issues to
broader social context
5. Lifelong Learning/Ethics
To demonstrate and practice ethical and professional responsibilities in the industry and society in the
large, through commitment and lifelong learning needed for successful professional career






4


PROGRAMME OUTCOMES (POs)
To demonstrate and apply knowledge of Mathematics, Science and engineering fundamentals in the following
experiments.
1 .To estimate HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. To determine total, temporary & permanent hardness of water by EDTA method.
3. To determine DO content of water sample by Winkler?s method.
4. To determine chloride content of water sample by Argentometric method.
5. To estimate copper content of the given solution by Iodometry.
6. To determine strength of given hydrochloric acid using pH meter.
7. To determine strength of acids in a mixture of acids using conductivity meter.
8. To determine iron content of the given solution using potentiometer.
9. To estimate iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. To estimate sodium and potassium present in water using flame photometer.
11. To determine molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. To determine Pseudo first order kinetics ? ester hydrolysis.
13. To determine Corrosion experiment ? weight loss method.
14. To estimate CMC.
15. To estimate Phase change in a solid.
16. To determine strength of strong acid vs strong base using conductivity meter.











5

BS8161 - CHEMISTRY LABORATORY
SYLLABUS


? To make the student to acquire practical skills in the determination of water quality
parameters through volumetric and instrumental analysis.

? ???? ??? ???? ?? ???? ? ? ?To acquaint the students with the determination of molecular weight of a polymer by
viscometery.

LIST OF EXPERIMENTS:
1. Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. Determination of total, temporary & permanent hardness of water by EDTA method.
3. Determination of DO content of water sample by Winkler?s method.
4. Determination of chloride content of water sample by Argentometric method.
5. Estimation of copper content of the given solution by Iodometry.
6. Determination of strength of given hydrochloric acid using pH meter.
7. Determination of strength of acids in a mixture of acids using conductivity meter.
8. Estimation of iron content of the given solution using potentiometer.
9. Estimation of iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. Estimation of sodium and potassium present in water using flame photometer.
11. Determination of molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. Pseudo first order kinetics ? ester hydrolysis.
13. Corrosion experiment ? weight loss method.
14. Determination of CMC.
15. Phase change in a solid.
16. Conductometric titration of strong acid vs strong base.




? The students will be outfitted with hands-on knowledge in the quantitative chemical
analysis of water quality related parameters.
COURSE OBJECTIVES
COURSE OUTCOMES
6


INDEX [ SEMESTER ? I ]


S.No.



Date


Experiment

Date of
submission



Mark


Signature

1.

Estimation of HCl using Na 2CO 3 as
primary standard and Determination of
alkalinity in water sample.



2.


Determination of total, temporary &
permanent hardness of water by EDTA
method.



3.


Determination of chloride content of water
sample by argentometric method.



4.


Determination of strength of given
hydrochloric acid using pH meter.



5.


Determination of strength of acids in a
mixture of acids using conductivity meter.



6.


Estimation of iron content of the given
solution using potentiometer.



7.





Conductometric titration of strong acid Vs
strong base.



8.



Estimation of copper content of the given
solution by Iodometry


9.
Estimation of sodium and potassium
present in water using flame photometer




7




CONTENTS


S.No.


NAME OF EXPERIMENT

PAGE
No.
SEMESTER - I
1.
Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in
water sample.
09
2. Determination of total, temporary & permanent hardness of water by EDTA method. 15
3. Determination of chloride content of water sample by Argentometric method. 21
4. Determination of strength of given hydrochloric acid using pH meter. 25
5. Determination of strength of acids in a mixture of acids using conductivity meter. 29
6. Estimation of iron content of the given solution using potentiometer. 33
7. Conductometric titration of strong acid Vs strong base.

39


42

8


Estimation of copper content of the given solution by Iodometry 43
9 Estimation of sodium and potassium present in water using flame photometer 47






8



SHORT PROCEDURE:

CONTENTS
TITRATION
Estimation of alkalinity in water sample
(Std HCl Vs water sample)

Burette solution

Std. HCl


Pipette solution

Water sample


Indicator


(i) Phenolphthalein
(ii) Methyl orange


End point

(i) Disappearance of pink colour
(ii) Appearance of reddish orange colour






Relationship
between P &M
Nature of alkalinity
Amount of individual
alkalinities
OH
-
HCO 3
-


CO 3
2-

P = M

only OH
-

P or M

?
0.0

0.0


2P = M

only CO 3
2-


2P or M


0.0


0.0


?

P =0, M?0

only HCO 3
-



M



0.0



?

0.0


2P > M


OH
-
&CO 3
2-


OH
-
= 2P-M
CO 3
2-
= 2(M-P)


?

0.0

?

P < ? M




HCO 3
-
&CO 3
2-


HCO 3
-
= M-2P
CO 3
2-
= 2P

0.0 ? ?




9





Expt. No. 1 DETERMINATION OF ALKALINITY IN WATER
AIM
To determine the type and amounts of alkalinity in the given water sample. A standard solution of Na 2CO 3
of strength ____N is given.

PRINCIPLE
Alkalinity in water is due to the presence of soluble hydroxides, bicarbonates and carbonates.
Determination of various types and amounts of alkalinity is easily carried out by titration with standard HCl
employing the indicators phenolphthalein and methyl orange independently or in succession.

The following reactions occur when different types of alkalinity are neutralized with acid.

OH
?
+ H
+
? H 2O completed at pH 8.2-9.0 ----- (1)

CO 3
2 ?
+ H
+
? HCO 3
?
----- (2)

HCO 3
?
+ H
+
? (H 2CO 3) ? H 2O + CO 2, completed at pH 4.2-5.5 ----- (3)

Neutralisation (1) & (2) will be notified by phenolphthalein end-point while all the three will be

accounted by
methyl orange end-point. Bicarbonate in eqn. (3) may be due to the existence of soluble free bicarbonate salts and
bicarbonates resulting from half neutralization of soluble carbonates (eqn. (2))

Various steps to be followed

a) A known volume of water sample is titrated against std. HCl using first phenolphthalein indicator till
end-point (P) and the titration is continued without break using methyl orange indicator till the end-
point (M).



10


Titration

Estimation of Alkalinity in water sample

Standard HCl Vs Water sample Indicator: 1. Phenolphthalein
2. Methyl Orange


S.No.
Volume
of water
sample (ml)
Burette Reading
Concordant value

Initial Phenolphthalein End
Point (P)
Methyl Orange End
Point (M)

1

2






CALCULATION

Hydroxide ion alkalinity
Volume of HCl (2P-M) = ???????ml

Strength of HCl = ???????? N

Volume of water sample = ???????...ml

Strength of water sample = Volume of HCl (2P-M) x Strength of HCl
Volume of water sample

=

? Hydroxide ion alkalinity in terms of
CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ??????.mg/l







11




b) From the magnitudes of the P & M, the nature of alkalinity can be arrived as follows:

(i) P = M => Presence of only OH
-

(ii) 2P = M => Presence of only CO 3
2-

(iii) P =0, M=0 => Presence of only HCO 3
-
(iv) 2P > M => Presence of OH
-
& CO 3
2-
(v) 2P < M => Presence of HCO 3
-
& CO 3
2-

(Mixture of OH
-
& HCO3
-
is not listed since they do not exist together and are considered equivalent to CO 3
2-
).

PROCEDURE
TITRATION
ESTIMATION OF ALKALINITY IN WATER SAMPLE

Exactly 20 ml of water sample is pipetted out into a clean conical flask. Few drops of phenolphthalein
indicator are added and titrated against a standardized HCl taken in the burette. The end point is the
disappearance of pink colour, which is noted as P. Few drops of methyl orange indicator is added to the same
solution. The solution turns to yellow. The titration is continued further by adding same HCl without break till the
end point is reached. The end point is the colour change from yellow to reddish orange.

The experiment is repeated to get concordant values. From the magnitudes of P & M values, the type of
alkalinity present in the water sample is inferred and the individual amounts are calculated and reported.










12


Carbonate ion alkalinity

Volume of HCl 2 (M ? P) = ??? ????????ml

Strength of HCl = ??.?????..???...N

Volume of water sample =........................................ml

Strength of water sample = Volume of HCl 2 (M ? P) x Strength of HCl
Volume of water sample

= ???????????.. N




? Carbonate ion alkalinity
in terms of CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ???????????mg/l

















13





RESULT

1) The type of alkalinity present in the water sample = -------------------------ions.

2) The individual amounts of alkalinity present in the water sample:
Hydroxide ion alkalinity

= ----------------- ppm
Carbonate ion alkalinity = ------------------ ppm
Bicarbonate ion alkalinity = ----------------- ppm





VIVA-VOCE


1. What is meant by alkalinity?
2. What are the ions responsible for alkalinity?
3. Why OH
-
and HCO 3
?
ions cannot exist together in water?
4. What are the ions responsible for alkalinity when 2P > M?
5. What is the pH range for both in acidic and basic solutions?
6. What is the colour of phenolphthalein in an acid and in an alkaline solution?
7. What is the purpose of using two indicators in same titration?
8. What are the possible combinations of ions for alkalinity?
9. How is the amount of alkalinity expressed?
10. What are the types of indicator used in this experiment?







14

SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II TITRATION III
Standardisation of
EDTA
(EDTA Vs Std
Hard water)
Determination of
total hardness
(Std EDTA Vs Hard
water sample)
Determination of
permanent hardness
(Std EDTA Vs Boiled
Hard water sample)

Burette solution

EDTA solution

EDTA solution

EDTA solution

Pipette solution

20ml Std. hard water

20 ml hard water sample

20ml boiled hard water sample

Indicator

2 drops of EBT

2 drops of EBT

2 drops of EBT

Additional soln.


Ammoniacal Buffer
solution (5ml)

Ammoniacal Buffer solution
(5ml)

Ammoniacal Buffer solution
(5ml)
End point Wine - red to Steel blue Wine - red to steel blue Wine - red to Steel blue




STANDARDISATION OF EDTA
Titration - I
Std. HARD WATER Vs EDTA Indicator: EBT

S. No.
Volume of std hard
water (ml)
Burette Reading Volume of
EDTA
(V 1) (ml)
Concordant value

Initial

Final



Volume of std .hard water taken = 20 ml
Volume of EDTA consumed (V 1) = --------------- ml
1 ml of std.hard water = 1mg of CaCO 3
20 ml of std hard water = 20 mg of CaCO 3

V 1 ml of EDTA solution containing 20 mg of CaCO 3
1 ml of EDTA solution = 20 / V 1 mg of CaCO 3
= -----------------------mg of CaCO 3


15

Expt. No. 2 DETERMINATION OF TOTAL, TEMPORARY AND
PERMANENT HARDNESS OF WATER

AIM
To estimate the amount of total, temporary & permanent hardness in the given sample of water.

PRINCIPLE
The estimation is based on the complexometric titration.

(i) Total hardness of water is estimated by titrating against EDTA using EBT indicator.
EBT+M ?[EBT-M] (unstable complex)
(EBT-M) (Unstable complex) +EDTA ? [EDTA-M] (stable complex) +EBT
EBT indicator forms wine- red colored complex with metal ions present in water. On addition of EDTA
metal ions preferably forms complexes with EDTA and steel blue EBT indicator is set free. Therefore
change of colour from wine- red to steel blue denotes the end point.

(ii) Temporary hardness is removed by boiling the water.
Ca (HCO 3) 2 ? CaCO 3 +CO 2 ?+H 2O
Mg (HCO 3) 2 ? Mg(OH) 2 +2CO 2 ?
The precipitate is filtered and the remaining permanent hardness is estimated using EDTA.

PROCEDURE

TITRATION ? I
STANDARDISATION OF EDTA

Pipette out 20ml of standard hard water into a 250ml conical flask. Add 5ml of buffer solution and 3
drops of eriochrome black T indictor. Titrate the solution with EDTA from the burette until the colour
changes from wine- red to steel blue at the end point. Repeat the titration for concordant values. Let the
titre value be V 1ml.


16


Titration-II
SAMPLE HARD WATER Vs Std EDTA Indicator: EBT

S.No. Volume of sample
hard water (ml)
Burette Reading Volume of
EDTA
(V 2) (ml)
Concordant value

Initial

Final




CALCULATION

Calculation of total hardness


Volume of EDTA consumed (V 2) = ------------------------- ml
1ml of EDTA = 20 / V 1 mg of CaCO 3
V 2 ml of EDTA = 20 / V 1 x V 2 mg of CaCO 3

( i.e), If 20ml of sample hard water contains 20 x V 2 mg of CaCO 3 / V 1

Then 1000ml of water sample = 20 x V 2 x 1000 / V 1 x 20 mg of CaCO 3

= 1000 x V 2 / V 1 mg of CaCO3

Total hardness of given water sample = ---------------------ppm









17



DETERMINATION OF TOTAL HARDNESS

Pipette out 20ml of sample hard water into a clean conical flask. Add 5ml of buffer solution and 4 -5
drops of Eriochrome black -T indicator. Titrate the wine - red coloured solution with EDTA from the burette until
the colour steel blue appears at the end point. Repeat the titration for concordant values. Let the titre value be
V 2ml.



DETERMINATION OF PERMANENT HARDNESS

Take 100ml of hard water sample in a 500ml beaker and boil gently for about 1hour. Cool, filter it into a
100ml standard flask and make the volume up to the mark. Take 20ml of this solution and proceed it in the same
way as in titration (I). The volume of EDTA consumed corresponds to the permanent hardness of the water
sample. Let the titre value be V 3ml. Temporary hardness is calculated by subtracting permanent hardness from
total hardness.





















18




DETERMINATION OF PERMANENT HARDNESS
BOILED SAMPLE WATER Vs Std. EDTA Indicator: EBT


S.No.
Volume of boiled
hard water (ml)
Burette Reading (ml) Volume of
EDTA
(ml)

Concordant value

Initial Final



CALCULATION OF PERMANENT HARDNESS


Volume of EDTA consumed V 3 = ---------------------ml

1ml of EDTA = 20 / V 1 mg of CaCO 3

V 3ml of EDTA = 20 / V 1 x V 3 mg of CaCO 3

(i.e) 20 ml of boiled sample hard water = 20 / V 1 x V 3 mg of CaCO 3

Then 1000ml of boiled water sample = 20 / V 1 x V 3 / 20 * 1000mg of CaCO 3

= 1000 x V 3 / V 1 mg of CaCO 3

permanent hardness of boiled water sample = -----------------ppm

Temporary hardness of the given water sample = Total hardness ? Permanent hardness

= ------------------ppm

19







RESULT

(i) Total hardness of the given sample water = -------------- ppm.
(ii) Permanent hardness of the given sample water = --------------- ppm.
(iii) Temporary hardness of the given sample water = ----------------ppm.







VIVA-VOCE

1. Define ? Hard water
2. What is the structure of EDTA?
3. How will you calculate temporary hardness?
4. What is the role of the buffer in EDTA titration?
5. What is the permissible limit of hardness in drinking water?
6. Name the hardness producing ions present in water.
7. Name two salts which are responsible for temporary hardness.
8. Why is CaCO 3 taken as the standard?
9. Write the expansion of EDTA.
10. What is meant by EBT?











20





SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II
Standardisation of
AgNO 3
Estimation of Chloride
Burette solution

AgNO 3 solution

Std. AgNO 3 solution

Pipette solution

20ml std KCl solution

20 ml water sample

Indicator

1ml K 2CrO 4

1ml K 2CrO 4


End point

yellow to reddish brown

yellow to reddish brown

Titration I
Std. AgNO3 Vs KCl Indicator: Potassium Chromate













CALCULATION

Volume of KCl (V 1) = ------- ml

Strength of KCl (N 1) = ------- N

Volume of Silver Nitrate (V 2) = -------- ml

Strength of Siver Nitrate V 1N 1
N 2 =
V 1

= --------------------- N

S.No.
Volume of KCl
(ml)
Burette Reading (ml)
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

21




Expt.No. 3 ESTIMATION OF CHLORIDE CONTENT IN WATER
(ARGENTOMETRIC METHOD)
AIM
To estimate the amount of chloride present in given water sample by Argentometric method (Mohr?s
method). You are provided with standard solution of NaCl of strength --------N and a approximately N/10 solution of
Silver nitrate.

PRINCIPLE
The Chloride ion in the form of NaCl, KCl, CaCl 2, MgCl 2 etc., present in the water sample can be estimated
by Argentometric method or known as Mohr?s method. It is an example for precipitation titration. The reaction
between std. Sodium chloride and Silver nitrate is given below.
AgNO 3 + NaCl ? AgCl ? + NaNO 3
The completion of reaction can be observed by employing potassium chromate as the indicator. The end
point is the colour change from yellow to reddish brown due to the following reaction.
2AgNO 3 + K 2CrO 4 ? Ag 2CrO 4 ? + 2KNO 3
Potassium chromate indicator will not be precipitated as silver chromate until all the chlorides in the solution
have been precipitated as AgCl Since a precipitation reaction takes place in preference, this reaction takes place
only at the end point.

PROCEDURE
TITRATION I: STANDARDISATION OF SILVER NITRATE
Pipette out 20ml of standard sodium or potassium chloride solution into a clean conical flask. Add 1ml of 5%
K 2CrO 4 indicator, as the solution turns yellow in colour. Titrate it against silver nitrate solution taken in the burette.
Observe the nearness of the end point through the formation of coagulated silver chloride precipitate at the bottom
of the flask. Now add the silver nitrate drop by drop until the solution gets a faint reddish brown tinge. Repeat the
titration for concordant value. Let the volume of silver nitrate be V 2ml.





22






TITRATION - II

Std AgNO3 Vs WATER SAMPLE Indicator: Potassium Chromate













CALCULATION

Volume of Silver Nitrate (V 3) = ------------ ml

Strength of Siver Nitrate (N 3) = ------------- N

Volume of Water sample (V 4) = -------------- ml

Strength of Water sample V 3 N 3
(N 4) =
V 4

= ----------------- N

Amount of Chloride ion present in 1000 ml of the water sample = Equivalent mass of HCl X 1000


= N 4 x 35.46 x 1000


= -----------------mg/l







S.No.
Volume of water
sample (ml)
Burette Reading
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

23





TITRATION - II
ESTIMATION OF CHLORIDE ION

Pipette out 40 ml of the given water sample into a clean conical flask.To this sample add 1ml of 5% K 2CrO 4
indicator and titrate it against the standardized silver nitrate solution taken in the burette and continue the titration
until the solution produces a reddish brown colour. Note down the end point and repeat the titration for
concordance. Let the volume be V 3ml.







RESULT

The amount of chloride ion present in the water sample = ----------------- mg/l.




VIVA-VOCE

1. Why is this method known as Argentometric method?
2.
What is the chemical reaction between AgNO 3 and Cl
-
ions present in water?

3.
What is the form of Chloride ion present in water?

4. What is the reaction between AgNO 3 and K 2CrO 4 ?
5. What is the name of the method used in this titration?
6. Name the link solution used in the determination.
7. Name the solution used to standardize AgNO 3.
8. What is the indicator used in the determination?
9. How will you calculate the amount of chloride ion in the given solution?
10. What is the colour change in the titration?




24




SHORT PROCEDURE


CONTENTS

TITRATION I

TITRATION II
Burette solution

Std Sodium Hydroxide

Std Sodium Hydroxide

Pipette solution

20 ml hydrochloric acid 20 ml hydrochloric acid
Additional solution


20 ml distilled water

20 ml distilled water


End point



Sudden increase in pH
pH gradual increase

Equivalent Weight of HCl = 36.5







ROUGH GRAPH FAIR GRAPH











pH
? pH/ ? V





Volume of NaOH
(ml)
Volume of NaOH
(ml)





25



Expt. No. 4 DETERMINATION OF STRENGTH OF HCl by pH METRY

AIM
To determine the strength of given HCl by pH metry. A standard solution of 0.1N NaOH is provided.

PRINCIPLE
The pH of a solution is related to H
+
ion concentration by the following formula.

. pH = -log [ H
+
]

pH of a solution is indirectly related to H
+
ion concentration. When NaOH is added slowly to HCl, H
+
ions
get neutralized by OH
-
ions. The pH increases slowly.

H
+
+ Cl
-
+ Na
+
+ OH
-
? Na
+
+ Cl
-
+H 2O

When all H
+
ions of HCl are neutralized at the end point, addition of NaOH causes high increase in pH
because of the addition of excess OH
-
ions.

MATERIALS REQUIRED
pH meter, Glass electrode, Burette, Pipette, Std.NaOH, approximately N/10 HCl .

PROCEDURE

The burette is washed with distilled water, rinsed with the given std. Sodium hydroxide and filled with the
same solution. Exactly 10ml of the given HCl solution is pipetted out into a clean beaker. It is then diluted to 50ml
with distilled water. A glass electrode is dipped into the solution and its terminals are connected to a pH meter.

26

TITRATION - I
S.No Volume of
NaOH (ml)
pH
1

2

3

4

5

6

7

8

9

10


TITRATION - II



CALCULATION

Volume of NaOH (V 1) = ------------------- ml ( titre value)
Strength of NaOH (N 1) = ------------------- N
Volume of HCl (V 2) = ------------------ml
Strength of HCl (N 2) = ------------------ N
N 2 = V 1 N 1 / V 2
Strength of HCl = -------------------- N
Amount of HCl present in 1000ml of the given solution = Strength x equivalent weight of HCl
= ------------------ X 36.5
= --------------------- g
S.No Volume of
NaOH (ml)
pH
11

12

13

14

15

16

17

18

19

20

S.No
Volume of
NaOH (ml)
pH ?pH ?V ?pH / ?V
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
27



Now NaOH is gradually added from the burette to HCl taken in the beaker. pH of the solution is noted for
each addition of NaOH. This process is continued until 5 readings are taken after the end point.
A fair titration is performed to find the exact end point.





RESULT

(i) Strength of the given HCl solution = ---------------- N
(ii) Amount of HCl present in a litre of the solution = ---------------- g


VIVA-VOCE

1. What is meant by pH?
2. What is the name of the reference electrode used ?
3. Why does pH value increase suddenly at the end point?
4. What is the indicator used in the titration?
5. What is the pH range of human blood?
6. What is the unit of pH?
7. How will you calculate the amount of HCl?
8. How is glass electrode represented?
9. Why is glass electrode known as ion selective electrode?
10. What is the chemical reaction involved in this titration?





28




SHORT PROCEDURE


CONTENTS
TITRATION
Burette solution

Std Sodium Hydroxide

Pipette solution

20 ml mixture of acid (HCl+ CH 3COOH)


Additional solution

20 ml distilled water


End point

Conductivity decreases-slowly increases-Sudden increase



Equivalent Weight of HCl = 36.5


Equivalent Weight of CH 3COOH = 60



MODEL GRAPH


Conductance
Volume of NaOH
Mixture of Acids






29




Expt. No. 5 CONDUCTOMETRIC TITRATION OF MIXTURE
OF ACIDS

AIM
To determine the amount of a strong acid and a weak acid present in the given solution.

PRINCIPLE

Solution of electrolytes conducts electricity due to the presence of ions. Since specific conductance of a
solution is proportional to the concentration of ions in it, conductance of the solution is measured during the titration.

HCl + NaOH ? NaCl + H 2O (I neutralization)

CH 3COOH + NaOH ? CH 3COONa + H 2O (II neutralization)

When a solution of HCl is treated with NaOH the fast moving hydrogen ions are progressively replaced by
slow moving sodium ions. As a result conductance of the solution decreases. This decrease will take place until the
first neutralisation point is reached. Further addition of alkali results in formation of sodium acetate.

Since sodium acetate is stronger than acetic acid conductivity slowly increases until all acetic acid is
completely neutralized.(II Neutralisation) This is due to the presence of fast moving OH
-
ions. Anymore addition of
alkali increases the conductance sharply.

PROCEDURE
The burette is filled with NaOH solution upto zero mark. The given unknown solution (mixture of a weak &
a strong acid) is transferred into a 100ml standard flask and made upto the mark with distilled water. 20ml of the
made up solution is pipetted out into a clean 100ml beaker. The solution is diluted to 20ml using distilled water. A
conductivity cell is dipped into the solution and the terminals are connected to a conductivity meter.
30


TITRATION


CALCULATION OF STRENGTH OF HCl
Volume of NaOH (V 1) = --------------- ml (titre value)
Strength of NaOH (N 1) = ---------------- N
Volume of HCl (V 2) = ------------ ml
Strength of HCl (N 2) = -------------- N

N 2 = V 1 N 1 / V 2
Strength of HCl = ---------------- N
CALCULATION OF STRENGTH OF CH3COOH
Volume of NaOH (V 1) = ------------ ml (titre value)
Strength of NaOH (N 1) = ------------ N
Volume of CH 3COOH (V 2) = ------------ ml
Strength of CH 3COOH (N 2) = ------------ N
N 2 = V 1 N 1 / V 2

Strength of CH 3COOH = ------------ N



S.No

Volume of NaOH
(ml)

Conductance (mho)

14

15

16

17
18
19
20

21
22
23
24
25
26

S.No

Volume of NaOH
(ml)

Conductance (mho)

1
2
3
4
5
6
7
8
9
10
11
12
13
31

The burette solution is added to the unknown solution in the beaker in 0.5 ml increments, the solution is
stirred using a glass rod, and the observed conductance values are read from the meter. The conductance values
show decrease in the initial values, then gradually increases and finally shows a steep increase. The titration hence
shows two end-points (i.e) I neutralization (weak acid) & II neutralization (strong acid).
The accurate end-point is obtained by plotting a graph between observed conductance Vs volume of
NaOH added.

RESULT
The strength of acids present in the given unknown solution are:
a) Strong acid = ---------------- N
b) Weak acid = -----------------N



VIVA-VOCE

1. What is weak acid?
2. How many end points are obtained from the graph? Comment two end points.
3. Why is the conductance increase in the first end point?
4. What mixture of acids used in this titration?
5. Write the neutralization reaction between CH 3COOH and NaOH.
6. What is the solution present in the conductivity cell?
7. What are strong and weak electrolytes?
8. Give an example for strong acid and weak acid.
9. What is the strong electrolyte of weak electrolyte?
10. Give an example for strong base.









32

SHORT PROCEDURE



















ROUGH GRAPH







EMF(mV)






Volume of Potassium dichromate (ml)

FAIR GRAPH









? E / ? V

Volume of Potassium dichromate (ml)




CONTENTS

TITRATION I

TITRATION II
Burette solution

Std Potassium dichromate

Std Potassium dichromate

Pipette solution

10 ml of FAS


10 ml of FAS



Additional
solution

20 ml distilled water+
10 ml of dil H 2SO 4


20 ml distilled water+
10 ml of dil H 2SO 4

End point

Sudden increase in EMF

EMF increases and decreases

Equivalent Weight of Ferrous ion = 55.85

33


Expt. No. 6 ESTIMATION OF FERROUS ION BY POTENTIOMETRIC
TITRATION

AIM
To estimate the amount of ferrous ion present in whole of the given solution potentiometrically. A standard
solution of potassium dichromate of strength -----------N is provided.

PRINCIPLE

Potentiometric titrations depend on measurement of emf between reference electrode and an indicator
electrode. When a solution of ferrous iron is titrated with a solution of potassium dichromate, the following redox
reaction takes place.

6Fe
2+
+ Cr 2O 7
2-
+ 14 H
+
? 6Fe
3+
+ 2Cr
3+
+ 7H 2O

During this titration Fe
2+
is converted in to Fe
3+
, whose concentration increases. At the end point, there
will be a sharp change due to sudden removal of all Fe
2+
ions.
The cell is set up by connecting this redox electrode with a calomel electrode as shown below:

Pt, Fe
2+
, Fe
3+
, II KCl , HgCl 2 (s), Hg

A graph between EMF measured against the volume of potassium dichromate added is drawn and the
end point is noted from the graph.

PROCEDURE

10ml of Ferrous solution is pipetted out into a 100 ml beaker. 10ml of dil.H 2SO 4 and 20ml of distilled water
are added. A platinum electrode and a calomel electrode are dipped into this solution and connected to the
potentiometer. Then 1ml of potassium dichromate is added to the solution and stirred well for 30 seconds. The
EMF is measured and the titration is continued by adding potassium dichromate in 1ml increments till five
measurements after the end point.



34


ROUGH TITRATION



S.No.

Volume of dichromate (ml)

EMF (mV)


1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.





35







A graph is drawn by plotting the emf against the volume of potassium dichromate and the end point range is
fixed.


About 20ml of Ferrous solution is pipetted out and the titration is continued by adding 0.1ml increaments of
potassium dichromate in the end point range. The emf is measured for each 0.1ml after stirring the solution well.


A graph is plotted between emf and the volume of potassium dichromate and also a first derivative graph is
plotted ( ? E/ ? V against vol. of K 2Cr 2O 7). The strength of Ferrous solution and the amount of Ferrous ion present are
calculated from the end point.



























36

FAIR TITRATION

S.No Volume of
Dichromate (ml)
Emf (mV) ?E ?V ?E/?V






















CALCULATION

Volume of Potassim dichromate (V 1) = -------------- ml
Normality of Potassium dichromate (N 1) = --------------- N
Volume of Ferrous sulphate (V 2) = --------------- ml
Normality of Ferrous sulphate (N 2) = --------------- N
Amount of Ferrous ion present in 1000ml of the solution = Normality X Equivalent weight of ferrous ion
= --------------- X 55.85 g

The amount of Ferrous ion present in the given solution = ----------------- g






37









RESULT

The amount of Ferrous ion present in the whole of the given solution = --------------- g.








VIVA-VOCE

1. What is EMF?
2. What is the basic principle of potentiometric titration?
3. Why does EMF increase during the titration?
4. Write the cell representation of the titration.
5. What is redox reaction?
6. What is the purpose of adding sulphuric acid?
7. What are the advantages of potentiometric titration?
8. How will you obtain the end point in the titration?
9. What is the name of the indicator electrode used in this titration?
10. What is the name of the reference electrode used?








38



SHORT PROCEDURE



CONTENTS

TITRATION
Burette solution

Sodium Hydroxide

Pipette solution

20 ml HCl


Additional solution

20 ml distilled water


End point

Decrease in conductance- increase in conductance

Equivalent Weight of HCl = 36.5
















Conductance

Volume of NaOH ( ml)









39


Expt.No. 7 CONDUCTOMETRIC TITRATION OF STRONG ACID
WITH STRONG BASE
AIM

To determine the strength of a strong acid by titrating a strong acid and strong base conductometrically. A
standard solution of NaOH of known strength ---------N is provided.

PRINCIPLE
Solution of electrolytes conducts electricity due to the presence of ions. The specific conductance of a
solution is proportional to the concentration of ions in it. The reaction between HCl and NaOH may be represented
as,
HCl +NaOH ? NaCl + H 2O

When a solution of hydrochloric acid is titrated with NaOH, the fast moving hydrogen ions are
progressively replaced by slow moving sodium ions. As a result conductance of the solution decreases, this
decrease in conductance will take place until the end point is reached. Further addition of alkali raises the
conductance sharply, as there is an excess of hydroxide ions.

A graph is drawn between volume of NaOH added and the conductance of solution. The exact end point
is intersection of the two lines.

PROCEDURE

The given HCl is made up in a 100ml standard flask. 10 ml of this solution is pipetted out in a beaker. The
burette is filled with standard sodium hydroxide upto the mark.

A conductivity cell is dipped into the beaker with HCl solution and connected to the terminals of the
conductivity bridge. About 1ml of STD NaOH is added and stirred well for 30 seconds. The conductance is
measured and the titration is continued till five measurements after the endpoint. A graph is plotted for the
conductance values against the volume of NaOH and the endpoint range is fixed.

40


TABLE



CALCULATION
Volume of Sodium Hydroxide (V 1) = ------------- ml
Normality of Sodium Hydroxide (N 1) = ------------- N
Volume of Strong acid (V 2) = ------------- ml
Normality of Strong acid (N 2) = V 1 N 1
V 2

The strength of the given strong acid = ------------- N




S.NO
Volume of NaOH
(ml)
Conductance
(mho)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
41

The above titration is repeated again and the exact endpoint is found out by adding in increments of 0.1ml
of NaOH in the end point range and continued after endpoint upto five readings.
A graph is plotted with the conductance values against the volume of NaOH and then the strength of the
strong acid is found out.


RESULT

The strength of the given strong acid is found to be = --------------- N







VIVA-VOCE

1. What is the basic principle of conductometric titration?
2. Why is conductance decreased and increased during the titration?
3. What is conductance mention its unit?
4. Give some examples for Strong acids and Strong bases.
5. Write the reaction between HCl and NaOH.
6. What is meant by strong base?
7. Explain why HCl is a strong acid?
8. Explain why the strength of burette solution is always greater than the pipette solution in conductometric
titration.
9. What is the equivalent weight of HCl and NaOH?
10. Write the formula that is used to calculate the amount of HCl.











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?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





3


PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)
1. Fundamentals
To provide students with a solid foundation in Mathematics, Science and fundamentals of engineering,
enabling them to apply, to find solutions for engineering problems and use this knowledge to acquire higher
education
2. Core Competence
To train the students in chemistry practicals so that they apply their knowledge and training to compare,
and to analyze various engineering industrial problems to find solutions
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice this enables
them to find solutions for the real time problems in industry, and to design products
4. Professionalism
To inculcate professional and effective communication skills, leadership qualities and team spirit in the
students to make them multi-faceted personalities and develop their ability to relate engineering issues to
broader social context
5. Lifelong Learning/Ethics
To demonstrate and practice ethical and professional responsibilities in the industry and society in the
large, through commitment and lifelong learning needed for successful professional career






4


PROGRAMME OUTCOMES (POs)
To demonstrate and apply knowledge of Mathematics, Science and engineering fundamentals in the following
experiments.
1 .To estimate HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. To determine total, temporary & permanent hardness of water by EDTA method.
3. To determine DO content of water sample by Winkler?s method.
4. To determine chloride content of water sample by Argentometric method.
5. To estimate copper content of the given solution by Iodometry.
6. To determine strength of given hydrochloric acid using pH meter.
7. To determine strength of acids in a mixture of acids using conductivity meter.
8. To determine iron content of the given solution using potentiometer.
9. To estimate iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. To estimate sodium and potassium present in water using flame photometer.
11. To determine molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. To determine Pseudo first order kinetics ? ester hydrolysis.
13. To determine Corrosion experiment ? weight loss method.
14. To estimate CMC.
15. To estimate Phase change in a solid.
16. To determine strength of strong acid vs strong base using conductivity meter.











5

BS8161 - CHEMISTRY LABORATORY
SYLLABUS


? To make the student to acquire practical skills in the determination of water quality
parameters through volumetric and instrumental analysis.

? ???? ??? ???? ?? ???? ? ? ?To acquaint the students with the determination of molecular weight of a polymer by
viscometery.

LIST OF EXPERIMENTS:
1. Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. Determination of total, temporary & permanent hardness of water by EDTA method.
3. Determination of DO content of water sample by Winkler?s method.
4. Determination of chloride content of water sample by Argentometric method.
5. Estimation of copper content of the given solution by Iodometry.
6. Determination of strength of given hydrochloric acid using pH meter.
7. Determination of strength of acids in a mixture of acids using conductivity meter.
8. Estimation of iron content of the given solution using potentiometer.
9. Estimation of iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. Estimation of sodium and potassium present in water using flame photometer.
11. Determination of molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. Pseudo first order kinetics ? ester hydrolysis.
13. Corrosion experiment ? weight loss method.
14. Determination of CMC.
15. Phase change in a solid.
16. Conductometric titration of strong acid vs strong base.




? The students will be outfitted with hands-on knowledge in the quantitative chemical
analysis of water quality related parameters.
COURSE OBJECTIVES
COURSE OUTCOMES
6


INDEX [ SEMESTER ? I ]


S.No.



Date


Experiment

Date of
submission



Mark


Signature

1.

Estimation of HCl using Na 2CO 3 as
primary standard and Determination of
alkalinity in water sample.



2.


Determination of total, temporary &
permanent hardness of water by EDTA
method.



3.


Determination of chloride content of water
sample by argentometric method.



4.


Determination of strength of given
hydrochloric acid using pH meter.



5.


Determination of strength of acids in a
mixture of acids using conductivity meter.



6.


Estimation of iron content of the given
solution using potentiometer.



7.





Conductometric titration of strong acid Vs
strong base.



8.



Estimation of copper content of the given
solution by Iodometry


9.
Estimation of sodium and potassium
present in water using flame photometer




7




CONTENTS


S.No.


NAME OF EXPERIMENT

PAGE
No.
SEMESTER - I
1.
Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in
water sample.
09
2. Determination of total, temporary & permanent hardness of water by EDTA method. 15
3. Determination of chloride content of water sample by Argentometric method. 21
4. Determination of strength of given hydrochloric acid using pH meter. 25
5. Determination of strength of acids in a mixture of acids using conductivity meter. 29
6. Estimation of iron content of the given solution using potentiometer. 33
7. Conductometric titration of strong acid Vs strong base.

39


42

8


Estimation of copper content of the given solution by Iodometry 43
9 Estimation of sodium and potassium present in water using flame photometer 47






8



SHORT PROCEDURE:

CONTENTS
TITRATION
Estimation of alkalinity in water sample
(Std HCl Vs water sample)

Burette solution

Std. HCl


Pipette solution

Water sample


Indicator


(i) Phenolphthalein
(ii) Methyl orange


End point

(i) Disappearance of pink colour
(ii) Appearance of reddish orange colour






Relationship
between P &M
Nature of alkalinity
Amount of individual
alkalinities
OH
-
HCO 3
-


CO 3
2-

P = M

only OH
-

P or M

?
0.0

0.0


2P = M

only CO 3
2-


2P or M


0.0


0.0


?

P =0, M?0

only HCO 3
-



M



0.0



?

0.0


2P > M


OH
-
&CO 3
2-


OH
-
= 2P-M
CO 3
2-
= 2(M-P)


?

0.0

?

P < ? M




HCO 3
-
&CO 3
2-


HCO 3
-
= M-2P
CO 3
2-
= 2P

0.0 ? ?




9





Expt. No. 1 DETERMINATION OF ALKALINITY IN WATER
AIM
To determine the type and amounts of alkalinity in the given water sample. A standard solution of Na 2CO 3
of strength ____N is given.

PRINCIPLE
Alkalinity in water is due to the presence of soluble hydroxides, bicarbonates and carbonates.
Determination of various types and amounts of alkalinity is easily carried out by titration with standard HCl
employing the indicators phenolphthalein and methyl orange independently or in succession.

The following reactions occur when different types of alkalinity are neutralized with acid.

OH
?
+ H
+
? H 2O completed at pH 8.2-9.0 ----- (1)

CO 3
2 ?
+ H
+
? HCO 3
?
----- (2)

HCO 3
?
+ H
+
? (H 2CO 3) ? H 2O + CO 2, completed at pH 4.2-5.5 ----- (3)

Neutralisation (1) & (2) will be notified by phenolphthalein end-point while all the three will be

accounted by
methyl orange end-point. Bicarbonate in eqn. (3) may be due to the existence of soluble free bicarbonate salts and
bicarbonates resulting from half neutralization of soluble carbonates (eqn. (2))

Various steps to be followed

a) A known volume of water sample is titrated against std. HCl using first phenolphthalein indicator till
end-point (P) and the titration is continued without break using methyl orange indicator till the end-
point (M).



10


Titration

Estimation of Alkalinity in water sample

Standard HCl Vs Water sample Indicator: 1. Phenolphthalein
2. Methyl Orange


S.No.
Volume
of water
sample (ml)
Burette Reading
Concordant value

Initial Phenolphthalein End
Point (P)
Methyl Orange End
Point (M)

1

2






CALCULATION

Hydroxide ion alkalinity
Volume of HCl (2P-M) = ???????ml

Strength of HCl = ???????? N

Volume of water sample = ???????...ml

Strength of water sample = Volume of HCl (2P-M) x Strength of HCl
Volume of water sample

=

? Hydroxide ion alkalinity in terms of
CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ??????.mg/l







11




b) From the magnitudes of the P & M, the nature of alkalinity can be arrived as follows:

(i) P = M => Presence of only OH
-

(ii) 2P = M => Presence of only CO 3
2-

(iii) P =0, M=0 => Presence of only HCO 3
-
(iv) 2P > M => Presence of OH
-
& CO 3
2-
(v) 2P < M => Presence of HCO 3
-
& CO 3
2-

(Mixture of OH
-
& HCO3
-
is not listed since they do not exist together and are considered equivalent to CO 3
2-
).

PROCEDURE
TITRATION
ESTIMATION OF ALKALINITY IN WATER SAMPLE

Exactly 20 ml of water sample is pipetted out into a clean conical flask. Few drops of phenolphthalein
indicator are added and titrated against a standardized HCl taken in the burette. The end point is the
disappearance of pink colour, which is noted as P. Few drops of methyl orange indicator is added to the same
solution. The solution turns to yellow. The titration is continued further by adding same HCl without break till the
end point is reached. The end point is the colour change from yellow to reddish orange.

The experiment is repeated to get concordant values. From the magnitudes of P & M values, the type of
alkalinity present in the water sample is inferred and the individual amounts are calculated and reported.










12


Carbonate ion alkalinity

Volume of HCl 2 (M ? P) = ??? ????????ml

Strength of HCl = ??.?????..???...N

Volume of water sample =........................................ml

Strength of water sample = Volume of HCl 2 (M ? P) x Strength of HCl
Volume of water sample

= ???????????.. N




? Carbonate ion alkalinity
in terms of CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ???????????mg/l

















13





RESULT

1) The type of alkalinity present in the water sample = -------------------------ions.

2) The individual amounts of alkalinity present in the water sample:
Hydroxide ion alkalinity

= ----------------- ppm
Carbonate ion alkalinity = ------------------ ppm
Bicarbonate ion alkalinity = ----------------- ppm





VIVA-VOCE


1. What is meant by alkalinity?
2. What are the ions responsible for alkalinity?
3. Why OH
-
and HCO 3
?
ions cannot exist together in water?
4. What are the ions responsible for alkalinity when 2P > M?
5. What is the pH range for both in acidic and basic solutions?
6. What is the colour of phenolphthalein in an acid and in an alkaline solution?
7. What is the purpose of using two indicators in same titration?
8. What are the possible combinations of ions for alkalinity?
9. How is the amount of alkalinity expressed?
10. What are the types of indicator used in this experiment?







14

SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II TITRATION III
Standardisation of
EDTA
(EDTA Vs Std
Hard water)
Determination of
total hardness
(Std EDTA Vs Hard
water sample)
Determination of
permanent hardness
(Std EDTA Vs Boiled
Hard water sample)

Burette solution

EDTA solution

EDTA solution

EDTA solution

Pipette solution

20ml Std. hard water

20 ml hard water sample

20ml boiled hard water sample

Indicator

2 drops of EBT

2 drops of EBT

2 drops of EBT

Additional soln.


Ammoniacal Buffer
solution (5ml)

Ammoniacal Buffer solution
(5ml)

Ammoniacal Buffer solution
(5ml)
End point Wine - red to Steel blue Wine - red to steel blue Wine - red to Steel blue




STANDARDISATION OF EDTA
Titration - I
Std. HARD WATER Vs EDTA Indicator: EBT

S. No.
Volume of std hard
water (ml)
Burette Reading Volume of
EDTA
(V 1) (ml)
Concordant value

Initial

Final



Volume of std .hard water taken = 20 ml
Volume of EDTA consumed (V 1) = --------------- ml
1 ml of std.hard water = 1mg of CaCO 3
20 ml of std hard water = 20 mg of CaCO 3

V 1 ml of EDTA solution containing 20 mg of CaCO 3
1 ml of EDTA solution = 20 / V 1 mg of CaCO 3
= -----------------------mg of CaCO 3


15

Expt. No. 2 DETERMINATION OF TOTAL, TEMPORARY AND
PERMANENT HARDNESS OF WATER

AIM
To estimate the amount of total, temporary & permanent hardness in the given sample of water.

PRINCIPLE
The estimation is based on the complexometric titration.

(i) Total hardness of water is estimated by titrating against EDTA using EBT indicator.
EBT+M ?[EBT-M] (unstable complex)
(EBT-M) (Unstable complex) +EDTA ? [EDTA-M] (stable complex) +EBT
EBT indicator forms wine- red colored complex with metal ions present in water. On addition of EDTA
metal ions preferably forms complexes with EDTA and steel blue EBT indicator is set free. Therefore
change of colour from wine- red to steel blue denotes the end point.

(ii) Temporary hardness is removed by boiling the water.
Ca (HCO 3) 2 ? CaCO 3 +CO 2 ?+H 2O
Mg (HCO 3) 2 ? Mg(OH) 2 +2CO 2 ?
The precipitate is filtered and the remaining permanent hardness is estimated using EDTA.

PROCEDURE

TITRATION ? I
STANDARDISATION OF EDTA

Pipette out 20ml of standard hard water into a 250ml conical flask. Add 5ml of buffer solution and 3
drops of eriochrome black T indictor. Titrate the solution with EDTA from the burette until the colour
changes from wine- red to steel blue at the end point. Repeat the titration for concordant values. Let the
titre value be V 1ml.


16


Titration-II
SAMPLE HARD WATER Vs Std EDTA Indicator: EBT

S.No. Volume of sample
hard water (ml)
Burette Reading Volume of
EDTA
(V 2) (ml)
Concordant value

Initial

Final




CALCULATION

Calculation of total hardness


Volume of EDTA consumed (V 2) = ------------------------- ml
1ml of EDTA = 20 / V 1 mg of CaCO 3
V 2 ml of EDTA = 20 / V 1 x V 2 mg of CaCO 3

( i.e), If 20ml of sample hard water contains 20 x V 2 mg of CaCO 3 / V 1

Then 1000ml of water sample = 20 x V 2 x 1000 / V 1 x 20 mg of CaCO 3

= 1000 x V 2 / V 1 mg of CaCO3

Total hardness of given water sample = ---------------------ppm









17



DETERMINATION OF TOTAL HARDNESS

Pipette out 20ml of sample hard water into a clean conical flask. Add 5ml of buffer solution and 4 -5
drops of Eriochrome black -T indicator. Titrate the wine - red coloured solution with EDTA from the burette until
the colour steel blue appears at the end point. Repeat the titration for concordant values. Let the titre value be
V 2ml.



DETERMINATION OF PERMANENT HARDNESS

Take 100ml of hard water sample in a 500ml beaker and boil gently for about 1hour. Cool, filter it into a
100ml standard flask and make the volume up to the mark. Take 20ml of this solution and proceed it in the same
way as in titration (I). The volume of EDTA consumed corresponds to the permanent hardness of the water
sample. Let the titre value be V 3ml. Temporary hardness is calculated by subtracting permanent hardness from
total hardness.





















18




DETERMINATION OF PERMANENT HARDNESS
BOILED SAMPLE WATER Vs Std. EDTA Indicator: EBT


S.No.
Volume of boiled
hard water (ml)
Burette Reading (ml) Volume of
EDTA
(ml)

Concordant value

Initial Final



CALCULATION OF PERMANENT HARDNESS


Volume of EDTA consumed V 3 = ---------------------ml

1ml of EDTA = 20 / V 1 mg of CaCO 3

V 3ml of EDTA = 20 / V 1 x V 3 mg of CaCO 3

(i.e) 20 ml of boiled sample hard water = 20 / V 1 x V 3 mg of CaCO 3

Then 1000ml of boiled water sample = 20 / V 1 x V 3 / 20 * 1000mg of CaCO 3

= 1000 x V 3 / V 1 mg of CaCO 3

permanent hardness of boiled water sample = -----------------ppm

Temporary hardness of the given water sample = Total hardness ? Permanent hardness

= ------------------ppm

19







RESULT

(i) Total hardness of the given sample water = -------------- ppm.
(ii) Permanent hardness of the given sample water = --------------- ppm.
(iii) Temporary hardness of the given sample water = ----------------ppm.







VIVA-VOCE

1. Define ? Hard water
2. What is the structure of EDTA?
3. How will you calculate temporary hardness?
4. What is the role of the buffer in EDTA titration?
5. What is the permissible limit of hardness in drinking water?
6. Name the hardness producing ions present in water.
7. Name two salts which are responsible for temporary hardness.
8. Why is CaCO 3 taken as the standard?
9. Write the expansion of EDTA.
10. What is meant by EBT?











20





SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II
Standardisation of
AgNO 3
Estimation of Chloride
Burette solution

AgNO 3 solution

Std. AgNO 3 solution

Pipette solution

20ml std KCl solution

20 ml water sample

Indicator

1ml K 2CrO 4

1ml K 2CrO 4


End point

yellow to reddish brown

yellow to reddish brown

Titration I
Std. AgNO3 Vs KCl Indicator: Potassium Chromate













CALCULATION

Volume of KCl (V 1) = ------- ml

Strength of KCl (N 1) = ------- N

Volume of Silver Nitrate (V 2) = -------- ml

Strength of Siver Nitrate V 1N 1
N 2 =
V 1

= --------------------- N

S.No.
Volume of KCl
(ml)
Burette Reading (ml)
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

21




Expt.No. 3 ESTIMATION OF CHLORIDE CONTENT IN WATER
(ARGENTOMETRIC METHOD)
AIM
To estimate the amount of chloride present in given water sample by Argentometric method (Mohr?s
method). You are provided with standard solution of NaCl of strength --------N and a approximately N/10 solution of
Silver nitrate.

PRINCIPLE
The Chloride ion in the form of NaCl, KCl, CaCl 2, MgCl 2 etc., present in the water sample can be estimated
by Argentometric method or known as Mohr?s method. It is an example for precipitation titration. The reaction
between std. Sodium chloride and Silver nitrate is given below.
AgNO 3 + NaCl ? AgCl ? + NaNO 3
The completion of reaction can be observed by employing potassium chromate as the indicator. The end
point is the colour change from yellow to reddish brown due to the following reaction.
2AgNO 3 + K 2CrO 4 ? Ag 2CrO 4 ? + 2KNO 3
Potassium chromate indicator will not be precipitated as silver chromate until all the chlorides in the solution
have been precipitated as AgCl Since a precipitation reaction takes place in preference, this reaction takes place
only at the end point.

PROCEDURE
TITRATION I: STANDARDISATION OF SILVER NITRATE
Pipette out 20ml of standard sodium or potassium chloride solution into a clean conical flask. Add 1ml of 5%
K 2CrO 4 indicator, as the solution turns yellow in colour. Titrate it against silver nitrate solution taken in the burette.
Observe the nearness of the end point through the formation of coagulated silver chloride precipitate at the bottom
of the flask. Now add the silver nitrate drop by drop until the solution gets a faint reddish brown tinge. Repeat the
titration for concordant value. Let the volume of silver nitrate be V 2ml.





22






TITRATION - II

Std AgNO3 Vs WATER SAMPLE Indicator: Potassium Chromate













CALCULATION

Volume of Silver Nitrate (V 3) = ------------ ml

Strength of Siver Nitrate (N 3) = ------------- N

Volume of Water sample (V 4) = -------------- ml

Strength of Water sample V 3 N 3
(N 4) =
V 4

= ----------------- N

Amount of Chloride ion present in 1000 ml of the water sample = Equivalent mass of HCl X 1000


= N 4 x 35.46 x 1000


= -----------------mg/l







S.No.
Volume of water
sample (ml)
Burette Reading
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

23





TITRATION - II
ESTIMATION OF CHLORIDE ION

Pipette out 40 ml of the given water sample into a clean conical flask.To this sample add 1ml of 5% K 2CrO 4
indicator and titrate it against the standardized silver nitrate solution taken in the burette and continue the titration
until the solution produces a reddish brown colour. Note down the end point and repeat the titration for
concordance. Let the volume be V 3ml.







RESULT

The amount of chloride ion present in the water sample = ----------------- mg/l.




VIVA-VOCE

1. Why is this method known as Argentometric method?
2.
What is the chemical reaction between AgNO 3 and Cl
-
ions present in water?

3.
What is the form of Chloride ion present in water?

4. What is the reaction between AgNO 3 and K 2CrO 4 ?
5. What is the name of the method used in this titration?
6. Name the link solution used in the determination.
7. Name the solution used to standardize AgNO 3.
8. What is the indicator used in the determination?
9. How will you calculate the amount of chloride ion in the given solution?
10. What is the colour change in the titration?




24




SHORT PROCEDURE


CONTENTS

TITRATION I

TITRATION II
Burette solution

Std Sodium Hydroxide

Std Sodium Hydroxide

Pipette solution

20 ml hydrochloric acid 20 ml hydrochloric acid
Additional solution


20 ml distilled water

20 ml distilled water


End point



Sudden increase in pH
pH gradual increase

Equivalent Weight of HCl = 36.5







ROUGH GRAPH FAIR GRAPH











pH
? pH/ ? V





Volume of NaOH
(ml)
Volume of NaOH
(ml)





25



Expt. No. 4 DETERMINATION OF STRENGTH OF HCl by pH METRY

AIM
To determine the strength of given HCl by pH metry. A standard solution of 0.1N NaOH is provided.

PRINCIPLE
The pH of a solution is related to H
+
ion concentration by the following formula.

. pH = -log [ H
+
]

pH of a solution is indirectly related to H
+
ion concentration. When NaOH is added slowly to HCl, H
+
ions
get neutralized by OH
-
ions. The pH increases slowly.

H
+
+ Cl
-
+ Na
+
+ OH
-
? Na
+
+ Cl
-
+H 2O

When all H
+
ions of HCl are neutralized at the end point, addition of NaOH causes high increase in pH
because of the addition of excess OH
-
ions.

MATERIALS REQUIRED
pH meter, Glass electrode, Burette, Pipette, Std.NaOH, approximately N/10 HCl .

PROCEDURE

The burette is washed with distilled water, rinsed with the given std. Sodium hydroxide and filled with the
same solution. Exactly 10ml of the given HCl solution is pipetted out into a clean beaker. It is then diluted to 50ml
with distilled water. A glass electrode is dipped into the solution and its terminals are connected to a pH meter.

26

TITRATION - I
S.No Volume of
NaOH (ml)
pH
1

2

3

4

5

6

7

8

9

10


TITRATION - II



CALCULATION

Volume of NaOH (V 1) = ------------------- ml ( titre value)
Strength of NaOH (N 1) = ------------------- N
Volume of HCl (V 2) = ------------------ml
Strength of HCl (N 2) = ------------------ N
N 2 = V 1 N 1 / V 2
Strength of HCl = -------------------- N
Amount of HCl present in 1000ml of the given solution = Strength x equivalent weight of HCl
= ------------------ X 36.5
= --------------------- g
S.No Volume of
NaOH (ml)
pH
11

12

13

14

15

16

17

18

19

20

S.No
Volume of
NaOH (ml)
pH ?pH ?V ?pH / ?V
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
27



Now NaOH is gradually added from the burette to HCl taken in the beaker. pH of the solution is noted for
each addition of NaOH. This process is continued until 5 readings are taken after the end point.
A fair titration is performed to find the exact end point.





RESULT

(i) Strength of the given HCl solution = ---------------- N
(ii) Amount of HCl present in a litre of the solution = ---------------- g


VIVA-VOCE

1. What is meant by pH?
2. What is the name of the reference electrode used ?
3. Why does pH value increase suddenly at the end point?
4. What is the indicator used in the titration?
5. What is the pH range of human blood?
6. What is the unit of pH?
7. How will you calculate the amount of HCl?
8. How is glass electrode represented?
9. Why is glass electrode known as ion selective electrode?
10. What is the chemical reaction involved in this titration?





28




SHORT PROCEDURE


CONTENTS
TITRATION
Burette solution

Std Sodium Hydroxide

Pipette solution

20 ml mixture of acid (HCl+ CH 3COOH)


Additional solution

20 ml distilled water


End point

Conductivity decreases-slowly increases-Sudden increase



Equivalent Weight of HCl = 36.5


Equivalent Weight of CH 3COOH = 60



MODEL GRAPH


Conductance
Volume of NaOH
Mixture of Acids






29




Expt. No. 5 CONDUCTOMETRIC TITRATION OF MIXTURE
OF ACIDS

AIM
To determine the amount of a strong acid and a weak acid present in the given solution.

PRINCIPLE

Solution of electrolytes conducts electricity due to the presence of ions. Since specific conductance of a
solution is proportional to the concentration of ions in it, conductance of the solution is measured during the titration.

HCl + NaOH ? NaCl + H 2O (I neutralization)

CH 3COOH + NaOH ? CH 3COONa + H 2O (II neutralization)

When a solution of HCl is treated with NaOH the fast moving hydrogen ions are progressively replaced by
slow moving sodium ions. As a result conductance of the solution decreases. This decrease will take place until the
first neutralisation point is reached. Further addition of alkali results in formation of sodium acetate.

Since sodium acetate is stronger than acetic acid conductivity slowly increases until all acetic acid is
completely neutralized.(II Neutralisation) This is due to the presence of fast moving OH
-
ions. Anymore addition of
alkali increases the conductance sharply.

PROCEDURE
The burette is filled with NaOH solution upto zero mark. The given unknown solution (mixture of a weak &
a strong acid) is transferred into a 100ml standard flask and made upto the mark with distilled water. 20ml of the
made up solution is pipetted out into a clean 100ml beaker. The solution is diluted to 20ml using distilled water. A
conductivity cell is dipped into the solution and the terminals are connected to a conductivity meter.
30


TITRATION


CALCULATION OF STRENGTH OF HCl
Volume of NaOH (V 1) = --------------- ml (titre value)
Strength of NaOH (N 1) = ---------------- N
Volume of HCl (V 2) = ------------ ml
Strength of HCl (N 2) = -------------- N

N 2 = V 1 N 1 / V 2
Strength of HCl = ---------------- N
CALCULATION OF STRENGTH OF CH3COOH
Volume of NaOH (V 1) = ------------ ml (titre value)
Strength of NaOH (N 1) = ------------ N
Volume of CH 3COOH (V 2) = ------------ ml
Strength of CH 3COOH (N 2) = ------------ N
N 2 = V 1 N 1 / V 2

Strength of CH 3COOH = ------------ N



S.No

Volume of NaOH
(ml)

Conductance (mho)

14

15

16

17
18
19
20

21
22
23
24
25
26

S.No

Volume of NaOH
(ml)

Conductance (mho)

1
2
3
4
5
6
7
8
9
10
11
12
13
31

The burette solution is added to the unknown solution in the beaker in 0.5 ml increments, the solution is
stirred using a glass rod, and the observed conductance values are read from the meter. The conductance values
show decrease in the initial values, then gradually increases and finally shows a steep increase. The titration hence
shows two end-points (i.e) I neutralization (weak acid) & II neutralization (strong acid).
The accurate end-point is obtained by plotting a graph between observed conductance Vs volume of
NaOH added.

RESULT
The strength of acids present in the given unknown solution are:
a) Strong acid = ---------------- N
b) Weak acid = -----------------N



VIVA-VOCE

1. What is weak acid?
2. How many end points are obtained from the graph? Comment two end points.
3. Why is the conductance increase in the first end point?
4. What mixture of acids used in this titration?
5. Write the neutralization reaction between CH 3COOH and NaOH.
6. What is the solution present in the conductivity cell?
7. What are strong and weak electrolytes?
8. Give an example for strong acid and weak acid.
9. What is the strong electrolyte of weak electrolyte?
10. Give an example for strong base.









32

SHORT PROCEDURE



















ROUGH GRAPH







EMF(mV)






Volume of Potassium dichromate (ml)

FAIR GRAPH









? E / ? V

Volume of Potassium dichromate (ml)




CONTENTS

TITRATION I

TITRATION II
Burette solution

Std Potassium dichromate

Std Potassium dichromate

Pipette solution

10 ml of FAS


10 ml of FAS



Additional
solution

20 ml distilled water+
10 ml of dil H 2SO 4


20 ml distilled water+
10 ml of dil H 2SO 4

End point

Sudden increase in EMF

EMF increases and decreases

Equivalent Weight of Ferrous ion = 55.85

33


Expt. No. 6 ESTIMATION OF FERROUS ION BY POTENTIOMETRIC
TITRATION

AIM
To estimate the amount of ferrous ion present in whole of the given solution potentiometrically. A standard
solution of potassium dichromate of strength -----------N is provided.

PRINCIPLE

Potentiometric titrations depend on measurement of emf between reference electrode and an indicator
electrode. When a solution of ferrous iron is titrated with a solution of potassium dichromate, the following redox
reaction takes place.

6Fe
2+
+ Cr 2O 7
2-
+ 14 H
+
? 6Fe
3+
+ 2Cr
3+
+ 7H 2O

During this titration Fe
2+
is converted in to Fe
3+
, whose concentration increases. At the end point, there
will be a sharp change due to sudden removal of all Fe
2+
ions.
The cell is set up by connecting this redox electrode with a calomel electrode as shown below:

Pt, Fe
2+
, Fe
3+
, II KCl , HgCl 2 (s), Hg

A graph between EMF measured against the volume of potassium dichromate added is drawn and the
end point is noted from the graph.

PROCEDURE

10ml of Ferrous solution is pipetted out into a 100 ml beaker. 10ml of dil.H 2SO 4 and 20ml of distilled water
are added. A platinum electrode and a calomel electrode are dipped into this solution and connected to the
potentiometer. Then 1ml of potassium dichromate is added to the solution and stirred well for 30 seconds. The
EMF is measured and the titration is continued by adding potassium dichromate in 1ml increments till five
measurements after the end point.



34


ROUGH TITRATION



S.No.

Volume of dichromate (ml)

EMF (mV)


1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.





35







A graph is drawn by plotting the emf against the volume of potassium dichromate and the end point range is
fixed.


About 20ml of Ferrous solution is pipetted out and the titration is continued by adding 0.1ml increaments of
potassium dichromate in the end point range. The emf is measured for each 0.1ml after stirring the solution well.


A graph is plotted between emf and the volume of potassium dichromate and also a first derivative graph is
plotted ( ? E/ ? V against vol. of K 2Cr 2O 7). The strength of Ferrous solution and the amount of Ferrous ion present are
calculated from the end point.



























36

FAIR TITRATION

S.No Volume of
Dichromate (ml)
Emf (mV) ?E ?V ?E/?V






















CALCULATION

Volume of Potassim dichromate (V 1) = -------------- ml
Normality of Potassium dichromate (N 1) = --------------- N
Volume of Ferrous sulphate (V 2) = --------------- ml
Normality of Ferrous sulphate (N 2) = --------------- N
Amount of Ferrous ion present in 1000ml of the solution = Normality X Equivalent weight of ferrous ion
= --------------- X 55.85 g

The amount of Ferrous ion present in the given solution = ----------------- g






37









RESULT

The amount of Ferrous ion present in the whole of the given solution = --------------- g.








VIVA-VOCE

1. What is EMF?
2. What is the basic principle of potentiometric titration?
3. Why does EMF increase during the titration?
4. Write the cell representation of the titration.
5. What is redox reaction?
6. What is the purpose of adding sulphuric acid?
7. What are the advantages of potentiometric titration?
8. How will you obtain the end point in the titration?
9. What is the name of the indicator electrode used in this titration?
10. What is the name of the reference electrode used?








38



SHORT PROCEDURE



CONTENTS

TITRATION
Burette solution

Sodium Hydroxide

Pipette solution

20 ml HCl


Additional solution

20 ml distilled water


End point

Decrease in conductance- increase in conductance

Equivalent Weight of HCl = 36.5
















Conductance

Volume of NaOH ( ml)









39


Expt.No. 7 CONDUCTOMETRIC TITRATION OF STRONG ACID
WITH STRONG BASE
AIM

To determine the strength of a strong acid by titrating a strong acid and strong base conductometrically. A
standard solution of NaOH of known strength ---------N is provided.

PRINCIPLE
Solution of electrolytes conducts electricity due to the presence of ions. The specific conductance of a
solution is proportional to the concentration of ions in it. The reaction between HCl and NaOH may be represented
as,
HCl +NaOH ? NaCl + H 2O

When a solution of hydrochloric acid is titrated with NaOH, the fast moving hydrogen ions are
progressively replaced by slow moving sodium ions. As a result conductance of the solution decreases, this
decrease in conductance will take place until the end point is reached. Further addition of alkali raises the
conductance sharply, as there is an excess of hydroxide ions.

A graph is drawn between volume of NaOH added and the conductance of solution. The exact end point
is intersection of the two lines.

PROCEDURE

The given HCl is made up in a 100ml standard flask. 10 ml of this solution is pipetted out in a beaker. The
burette is filled with standard sodium hydroxide upto the mark.

A conductivity cell is dipped into the beaker with HCl solution and connected to the terminals of the
conductivity bridge. About 1ml of STD NaOH is added and stirred well for 30 seconds. The conductance is
measured and the titration is continued till five measurements after the endpoint. A graph is plotted for the
conductance values against the volume of NaOH and the endpoint range is fixed.

40


TABLE



CALCULATION
Volume of Sodium Hydroxide (V 1) = ------------- ml
Normality of Sodium Hydroxide (N 1) = ------------- N
Volume of Strong acid (V 2) = ------------- ml
Normality of Strong acid (N 2) = V 1 N 1
V 2

The strength of the given strong acid = ------------- N




S.NO
Volume of NaOH
(ml)
Conductance
(mho)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
41

The above titration is repeated again and the exact endpoint is found out by adding in increments of 0.1ml
of NaOH in the end point range and continued after endpoint upto five readings.
A graph is plotted with the conductance values against the volume of NaOH and then the strength of the
strong acid is found out.


RESULT

The strength of the given strong acid is found to be = --------------- N







VIVA-VOCE

1. What is the basic principle of conductometric titration?
2. Why is conductance decreased and increased during the titration?
3. What is conductance mention its unit?
4. Give some examples for Strong acids and Strong bases.
5. Write the reaction between HCl and NaOH.
6. What is meant by strong base?
7. Explain why HCl is a strong acid?
8. Explain why the strength of burette solution is always greater than the pipette solution in conductometric
titration.
9. What is the equivalent weight of HCl and NaOH?
10. Write the formula that is used to calculate the amount of HCl.











42

ESTIMATION OF COPPER

Alloy solution Vs Std. Na2S2O3 (Thio) Indicator: Starch

S.No.
Volume of
Alloy Solution
(ml)
Burette Reading (ml) Volume of
Thio
(ml)
Concordant value
(ml)
Initial Final

1.

2.

3.












CALCULATION
Volume of Na 2S 2O 3 V 1 = ------------- ml

Strength of Na 2S 2O 3 N 1 = ------------- N

Volume of brass solution V 2 = ------------- ml

Strength of brass solution N 2 = ------------- ?

= V 1 x N I / /V 2

= -------------

Strength of copper solution is = ------------- N



















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?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





3


PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)
1. Fundamentals
To provide students with a solid foundation in Mathematics, Science and fundamentals of engineering,
enabling them to apply, to find solutions for engineering problems and use this knowledge to acquire higher
education
2. Core Competence
To train the students in chemistry practicals so that they apply their knowledge and training to compare,
and to analyze various engineering industrial problems to find solutions
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice this enables
them to find solutions for the real time problems in industry, and to design products
4. Professionalism
To inculcate professional and effective communication skills, leadership qualities and team spirit in the
students to make them multi-faceted personalities and develop their ability to relate engineering issues to
broader social context
5. Lifelong Learning/Ethics
To demonstrate and practice ethical and professional responsibilities in the industry and society in the
large, through commitment and lifelong learning needed for successful professional career






4


PROGRAMME OUTCOMES (POs)
To demonstrate and apply knowledge of Mathematics, Science and engineering fundamentals in the following
experiments.
1 .To estimate HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. To determine total, temporary & permanent hardness of water by EDTA method.
3. To determine DO content of water sample by Winkler?s method.
4. To determine chloride content of water sample by Argentometric method.
5. To estimate copper content of the given solution by Iodometry.
6. To determine strength of given hydrochloric acid using pH meter.
7. To determine strength of acids in a mixture of acids using conductivity meter.
8. To determine iron content of the given solution using potentiometer.
9. To estimate iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. To estimate sodium and potassium present in water using flame photometer.
11. To determine molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. To determine Pseudo first order kinetics ? ester hydrolysis.
13. To determine Corrosion experiment ? weight loss method.
14. To estimate CMC.
15. To estimate Phase change in a solid.
16. To determine strength of strong acid vs strong base using conductivity meter.











5

BS8161 - CHEMISTRY LABORATORY
SYLLABUS


? To make the student to acquire practical skills in the determination of water quality
parameters through volumetric and instrumental analysis.

? ???? ??? ???? ?? ???? ? ? ?To acquaint the students with the determination of molecular weight of a polymer by
viscometery.

LIST OF EXPERIMENTS:
1. Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. Determination of total, temporary & permanent hardness of water by EDTA method.
3. Determination of DO content of water sample by Winkler?s method.
4. Determination of chloride content of water sample by Argentometric method.
5. Estimation of copper content of the given solution by Iodometry.
6. Determination of strength of given hydrochloric acid using pH meter.
7. Determination of strength of acids in a mixture of acids using conductivity meter.
8. Estimation of iron content of the given solution using potentiometer.
9. Estimation of iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. Estimation of sodium and potassium present in water using flame photometer.
11. Determination of molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. Pseudo first order kinetics ? ester hydrolysis.
13. Corrosion experiment ? weight loss method.
14. Determination of CMC.
15. Phase change in a solid.
16. Conductometric titration of strong acid vs strong base.




? The students will be outfitted with hands-on knowledge in the quantitative chemical
analysis of water quality related parameters.
COURSE OBJECTIVES
COURSE OUTCOMES
6


INDEX [ SEMESTER ? I ]


S.No.



Date


Experiment

Date of
submission



Mark


Signature

1.

Estimation of HCl using Na 2CO 3 as
primary standard and Determination of
alkalinity in water sample.



2.


Determination of total, temporary &
permanent hardness of water by EDTA
method.



3.


Determination of chloride content of water
sample by argentometric method.



4.


Determination of strength of given
hydrochloric acid using pH meter.



5.


Determination of strength of acids in a
mixture of acids using conductivity meter.



6.


Estimation of iron content of the given
solution using potentiometer.



7.





Conductometric titration of strong acid Vs
strong base.



8.



Estimation of copper content of the given
solution by Iodometry


9.
Estimation of sodium and potassium
present in water using flame photometer




7




CONTENTS


S.No.


NAME OF EXPERIMENT

PAGE
No.
SEMESTER - I
1.
Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in
water sample.
09
2. Determination of total, temporary & permanent hardness of water by EDTA method. 15
3. Determination of chloride content of water sample by Argentometric method. 21
4. Determination of strength of given hydrochloric acid using pH meter. 25
5. Determination of strength of acids in a mixture of acids using conductivity meter. 29
6. Estimation of iron content of the given solution using potentiometer. 33
7. Conductometric titration of strong acid Vs strong base.

39


42

8


Estimation of copper content of the given solution by Iodometry 43
9 Estimation of sodium and potassium present in water using flame photometer 47






8



SHORT PROCEDURE:

CONTENTS
TITRATION
Estimation of alkalinity in water sample
(Std HCl Vs water sample)

Burette solution

Std. HCl


Pipette solution

Water sample


Indicator


(i) Phenolphthalein
(ii) Methyl orange


End point

(i) Disappearance of pink colour
(ii) Appearance of reddish orange colour






Relationship
between P &M
Nature of alkalinity
Amount of individual
alkalinities
OH
-
HCO 3
-


CO 3
2-

P = M

only OH
-

P or M

?
0.0

0.0


2P = M

only CO 3
2-


2P or M


0.0


0.0


?

P =0, M?0

only HCO 3
-



M



0.0



?

0.0


2P > M


OH
-
&CO 3
2-


OH
-
= 2P-M
CO 3
2-
= 2(M-P)


?

0.0

?

P < ? M




HCO 3
-
&CO 3
2-


HCO 3
-
= M-2P
CO 3
2-
= 2P

0.0 ? ?




9





Expt. No. 1 DETERMINATION OF ALKALINITY IN WATER
AIM
To determine the type and amounts of alkalinity in the given water sample. A standard solution of Na 2CO 3
of strength ____N is given.

PRINCIPLE
Alkalinity in water is due to the presence of soluble hydroxides, bicarbonates and carbonates.
Determination of various types and amounts of alkalinity is easily carried out by titration with standard HCl
employing the indicators phenolphthalein and methyl orange independently or in succession.

The following reactions occur when different types of alkalinity are neutralized with acid.

OH
?
+ H
+
? H 2O completed at pH 8.2-9.0 ----- (1)

CO 3
2 ?
+ H
+
? HCO 3
?
----- (2)

HCO 3
?
+ H
+
? (H 2CO 3) ? H 2O + CO 2, completed at pH 4.2-5.5 ----- (3)

Neutralisation (1) & (2) will be notified by phenolphthalein end-point while all the three will be

accounted by
methyl orange end-point. Bicarbonate in eqn. (3) may be due to the existence of soluble free bicarbonate salts and
bicarbonates resulting from half neutralization of soluble carbonates (eqn. (2))

Various steps to be followed

a) A known volume of water sample is titrated against std. HCl using first phenolphthalein indicator till
end-point (P) and the titration is continued without break using methyl orange indicator till the end-
point (M).



10


Titration

Estimation of Alkalinity in water sample

Standard HCl Vs Water sample Indicator: 1. Phenolphthalein
2. Methyl Orange


S.No.
Volume
of water
sample (ml)
Burette Reading
Concordant value

Initial Phenolphthalein End
Point (P)
Methyl Orange End
Point (M)

1

2






CALCULATION

Hydroxide ion alkalinity
Volume of HCl (2P-M) = ???????ml

Strength of HCl = ???????? N

Volume of water sample = ???????...ml

Strength of water sample = Volume of HCl (2P-M) x Strength of HCl
Volume of water sample

=

? Hydroxide ion alkalinity in terms of
CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ??????.mg/l







11




b) From the magnitudes of the P & M, the nature of alkalinity can be arrived as follows:

(i) P = M => Presence of only OH
-

(ii) 2P = M => Presence of only CO 3
2-

(iii) P =0, M=0 => Presence of only HCO 3
-
(iv) 2P > M => Presence of OH
-
& CO 3
2-
(v) 2P < M => Presence of HCO 3
-
& CO 3
2-

(Mixture of OH
-
& HCO3
-
is not listed since they do not exist together and are considered equivalent to CO 3
2-
).

PROCEDURE
TITRATION
ESTIMATION OF ALKALINITY IN WATER SAMPLE

Exactly 20 ml of water sample is pipetted out into a clean conical flask. Few drops of phenolphthalein
indicator are added and titrated against a standardized HCl taken in the burette. The end point is the
disappearance of pink colour, which is noted as P. Few drops of methyl orange indicator is added to the same
solution. The solution turns to yellow. The titration is continued further by adding same HCl without break till the
end point is reached. The end point is the colour change from yellow to reddish orange.

The experiment is repeated to get concordant values. From the magnitudes of P & M values, the type of
alkalinity present in the water sample is inferred and the individual amounts are calculated and reported.










12


Carbonate ion alkalinity

Volume of HCl 2 (M ? P) = ??? ????????ml

Strength of HCl = ??.?????..???...N

Volume of water sample =........................................ml

Strength of water sample = Volume of HCl 2 (M ? P) x Strength of HCl
Volume of water sample

= ???????????.. N




? Carbonate ion alkalinity
in terms of CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ???????????mg/l

















13





RESULT

1) The type of alkalinity present in the water sample = -------------------------ions.

2) The individual amounts of alkalinity present in the water sample:
Hydroxide ion alkalinity

= ----------------- ppm
Carbonate ion alkalinity = ------------------ ppm
Bicarbonate ion alkalinity = ----------------- ppm





VIVA-VOCE


1. What is meant by alkalinity?
2. What are the ions responsible for alkalinity?
3. Why OH
-
and HCO 3
?
ions cannot exist together in water?
4. What are the ions responsible for alkalinity when 2P > M?
5. What is the pH range for both in acidic and basic solutions?
6. What is the colour of phenolphthalein in an acid and in an alkaline solution?
7. What is the purpose of using two indicators in same titration?
8. What are the possible combinations of ions for alkalinity?
9. How is the amount of alkalinity expressed?
10. What are the types of indicator used in this experiment?







14

SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II TITRATION III
Standardisation of
EDTA
(EDTA Vs Std
Hard water)
Determination of
total hardness
(Std EDTA Vs Hard
water sample)
Determination of
permanent hardness
(Std EDTA Vs Boiled
Hard water sample)

Burette solution

EDTA solution

EDTA solution

EDTA solution

Pipette solution

20ml Std. hard water

20 ml hard water sample

20ml boiled hard water sample

Indicator

2 drops of EBT

2 drops of EBT

2 drops of EBT

Additional soln.


Ammoniacal Buffer
solution (5ml)

Ammoniacal Buffer solution
(5ml)

Ammoniacal Buffer solution
(5ml)
End point Wine - red to Steel blue Wine - red to steel blue Wine - red to Steel blue




STANDARDISATION OF EDTA
Titration - I
Std. HARD WATER Vs EDTA Indicator: EBT

S. No.
Volume of std hard
water (ml)
Burette Reading Volume of
EDTA
(V 1) (ml)
Concordant value

Initial

Final



Volume of std .hard water taken = 20 ml
Volume of EDTA consumed (V 1) = --------------- ml
1 ml of std.hard water = 1mg of CaCO 3
20 ml of std hard water = 20 mg of CaCO 3

V 1 ml of EDTA solution containing 20 mg of CaCO 3
1 ml of EDTA solution = 20 / V 1 mg of CaCO 3
= -----------------------mg of CaCO 3


15

Expt. No. 2 DETERMINATION OF TOTAL, TEMPORARY AND
PERMANENT HARDNESS OF WATER

AIM
To estimate the amount of total, temporary & permanent hardness in the given sample of water.

PRINCIPLE
The estimation is based on the complexometric titration.

(i) Total hardness of water is estimated by titrating against EDTA using EBT indicator.
EBT+M ?[EBT-M] (unstable complex)
(EBT-M) (Unstable complex) +EDTA ? [EDTA-M] (stable complex) +EBT
EBT indicator forms wine- red colored complex with metal ions present in water. On addition of EDTA
metal ions preferably forms complexes with EDTA and steel blue EBT indicator is set free. Therefore
change of colour from wine- red to steel blue denotes the end point.

(ii) Temporary hardness is removed by boiling the water.
Ca (HCO 3) 2 ? CaCO 3 +CO 2 ?+H 2O
Mg (HCO 3) 2 ? Mg(OH) 2 +2CO 2 ?
The precipitate is filtered and the remaining permanent hardness is estimated using EDTA.

PROCEDURE

TITRATION ? I
STANDARDISATION OF EDTA

Pipette out 20ml of standard hard water into a 250ml conical flask. Add 5ml of buffer solution and 3
drops of eriochrome black T indictor. Titrate the solution with EDTA from the burette until the colour
changes from wine- red to steel blue at the end point. Repeat the titration for concordant values. Let the
titre value be V 1ml.


16


Titration-II
SAMPLE HARD WATER Vs Std EDTA Indicator: EBT

S.No. Volume of sample
hard water (ml)
Burette Reading Volume of
EDTA
(V 2) (ml)
Concordant value

Initial

Final




CALCULATION

Calculation of total hardness


Volume of EDTA consumed (V 2) = ------------------------- ml
1ml of EDTA = 20 / V 1 mg of CaCO 3
V 2 ml of EDTA = 20 / V 1 x V 2 mg of CaCO 3

( i.e), If 20ml of sample hard water contains 20 x V 2 mg of CaCO 3 / V 1

Then 1000ml of water sample = 20 x V 2 x 1000 / V 1 x 20 mg of CaCO 3

= 1000 x V 2 / V 1 mg of CaCO3

Total hardness of given water sample = ---------------------ppm









17



DETERMINATION OF TOTAL HARDNESS

Pipette out 20ml of sample hard water into a clean conical flask. Add 5ml of buffer solution and 4 -5
drops of Eriochrome black -T indicator. Titrate the wine - red coloured solution with EDTA from the burette until
the colour steel blue appears at the end point. Repeat the titration for concordant values. Let the titre value be
V 2ml.



DETERMINATION OF PERMANENT HARDNESS

Take 100ml of hard water sample in a 500ml beaker and boil gently for about 1hour. Cool, filter it into a
100ml standard flask and make the volume up to the mark. Take 20ml of this solution and proceed it in the same
way as in titration (I). The volume of EDTA consumed corresponds to the permanent hardness of the water
sample. Let the titre value be V 3ml. Temporary hardness is calculated by subtracting permanent hardness from
total hardness.





















18




DETERMINATION OF PERMANENT HARDNESS
BOILED SAMPLE WATER Vs Std. EDTA Indicator: EBT


S.No.
Volume of boiled
hard water (ml)
Burette Reading (ml) Volume of
EDTA
(ml)

Concordant value

Initial Final



CALCULATION OF PERMANENT HARDNESS


Volume of EDTA consumed V 3 = ---------------------ml

1ml of EDTA = 20 / V 1 mg of CaCO 3

V 3ml of EDTA = 20 / V 1 x V 3 mg of CaCO 3

(i.e) 20 ml of boiled sample hard water = 20 / V 1 x V 3 mg of CaCO 3

Then 1000ml of boiled water sample = 20 / V 1 x V 3 / 20 * 1000mg of CaCO 3

= 1000 x V 3 / V 1 mg of CaCO 3

permanent hardness of boiled water sample = -----------------ppm

Temporary hardness of the given water sample = Total hardness ? Permanent hardness

= ------------------ppm

19







RESULT

(i) Total hardness of the given sample water = -------------- ppm.
(ii) Permanent hardness of the given sample water = --------------- ppm.
(iii) Temporary hardness of the given sample water = ----------------ppm.







VIVA-VOCE

1. Define ? Hard water
2. What is the structure of EDTA?
3. How will you calculate temporary hardness?
4. What is the role of the buffer in EDTA titration?
5. What is the permissible limit of hardness in drinking water?
6. Name the hardness producing ions present in water.
7. Name two salts which are responsible for temporary hardness.
8. Why is CaCO 3 taken as the standard?
9. Write the expansion of EDTA.
10. What is meant by EBT?











20





SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II
Standardisation of
AgNO 3
Estimation of Chloride
Burette solution

AgNO 3 solution

Std. AgNO 3 solution

Pipette solution

20ml std KCl solution

20 ml water sample

Indicator

1ml K 2CrO 4

1ml K 2CrO 4


End point

yellow to reddish brown

yellow to reddish brown

Titration I
Std. AgNO3 Vs KCl Indicator: Potassium Chromate













CALCULATION

Volume of KCl (V 1) = ------- ml

Strength of KCl (N 1) = ------- N

Volume of Silver Nitrate (V 2) = -------- ml

Strength of Siver Nitrate V 1N 1
N 2 =
V 1

= --------------------- N

S.No.
Volume of KCl
(ml)
Burette Reading (ml)
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

21




Expt.No. 3 ESTIMATION OF CHLORIDE CONTENT IN WATER
(ARGENTOMETRIC METHOD)
AIM
To estimate the amount of chloride present in given water sample by Argentometric method (Mohr?s
method). You are provided with standard solution of NaCl of strength --------N and a approximately N/10 solution of
Silver nitrate.

PRINCIPLE
The Chloride ion in the form of NaCl, KCl, CaCl 2, MgCl 2 etc., present in the water sample can be estimated
by Argentometric method or known as Mohr?s method. It is an example for precipitation titration. The reaction
between std. Sodium chloride and Silver nitrate is given below.
AgNO 3 + NaCl ? AgCl ? + NaNO 3
The completion of reaction can be observed by employing potassium chromate as the indicator. The end
point is the colour change from yellow to reddish brown due to the following reaction.
2AgNO 3 + K 2CrO 4 ? Ag 2CrO 4 ? + 2KNO 3
Potassium chromate indicator will not be precipitated as silver chromate until all the chlorides in the solution
have been precipitated as AgCl Since a precipitation reaction takes place in preference, this reaction takes place
only at the end point.

PROCEDURE
TITRATION I: STANDARDISATION OF SILVER NITRATE
Pipette out 20ml of standard sodium or potassium chloride solution into a clean conical flask. Add 1ml of 5%
K 2CrO 4 indicator, as the solution turns yellow in colour. Titrate it against silver nitrate solution taken in the burette.
Observe the nearness of the end point through the formation of coagulated silver chloride precipitate at the bottom
of the flask. Now add the silver nitrate drop by drop until the solution gets a faint reddish brown tinge. Repeat the
titration for concordant value. Let the volume of silver nitrate be V 2ml.





22






TITRATION - II

Std AgNO3 Vs WATER SAMPLE Indicator: Potassium Chromate













CALCULATION

Volume of Silver Nitrate (V 3) = ------------ ml

Strength of Siver Nitrate (N 3) = ------------- N

Volume of Water sample (V 4) = -------------- ml

Strength of Water sample V 3 N 3
(N 4) =
V 4

= ----------------- N

Amount of Chloride ion present in 1000 ml of the water sample = Equivalent mass of HCl X 1000


= N 4 x 35.46 x 1000


= -----------------mg/l







S.No.
Volume of water
sample (ml)
Burette Reading
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

23





TITRATION - II
ESTIMATION OF CHLORIDE ION

Pipette out 40 ml of the given water sample into a clean conical flask.To this sample add 1ml of 5% K 2CrO 4
indicator and titrate it against the standardized silver nitrate solution taken in the burette and continue the titration
until the solution produces a reddish brown colour. Note down the end point and repeat the titration for
concordance. Let the volume be V 3ml.







RESULT

The amount of chloride ion present in the water sample = ----------------- mg/l.




VIVA-VOCE

1. Why is this method known as Argentometric method?
2.
What is the chemical reaction between AgNO 3 and Cl
-
ions present in water?

3.
What is the form of Chloride ion present in water?

4. What is the reaction between AgNO 3 and K 2CrO 4 ?
5. What is the name of the method used in this titration?
6. Name the link solution used in the determination.
7. Name the solution used to standardize AgNO 3.
8. What is the indicator used in the determination?
9. How will you calculate the amount of chloride ion in the given solution?
10. What is the colour change in the titration?




24




SHORT PROCEDURE


CONTENTS

TITRATION I

TITRATION II
Burette solution

Std Sodium Hydroxide

Std Sodium Hydroxide

Pipette solution

20 ml hydrochloric acid 20 ml hydrochloric acid
Additional solution


20 ml distilled water

20 ml distilled water


End point



Sudden increase in pH
pH gradual increase

Equivalent Weight of HCl = 36.5







ROUGH GRAPH FAIR GRAPH











pH
? pH/ ? V





Volume of NaOH
(ml)
Volume of NaOH
(ml)





25



Expt. No. 4 DETERMINATION OF STRENGTH OF HCl by pH METRY

AIM
To determine the strength of given HCl by pH metry. A standard solution of 0.1N NaOH is provided.

PRINCIPLE
The pH of a solution is related to H
+
ion concentration by the following formula.

. pH = -log [ H
+
]

pH of a solution is indirectly related to H
+
ion concentration. When NaOH is added slowly to HCl, H
+
ions
get neutralized by OH
-
ions. The pH increases slowly.

H
+
+ Cl
-
+ Na
+
+ OH
-
? Na
+
+ Cl
-
+H 2O

When all H
+
ions of HCl are neutralized at the end point, addition of NaOH causes high increase in pH
because of the addition of excess OH
-
ions.

MATERIALS REQUIRED
pH meter, Glass electrode, Burette, Pipette, Std.NaOH, approximately N/10 HCl .

PROCEDURE

The burette is washed with distilled water, rinsed with the given std. Sodium hydroxide and filled with the
same solution. Exactly 10ml of the given HCl solution is pipetted out into a clean beaker. It is then diluted to 50ml
with distilled water. A glass electrode is dipped into the solution and its terminals are connected to a pH meter.

26

TITRATION - I
S.No Volume of
NaOH (ml)
pH
1

2

3

4

5

6

7

8

9

10


TITRATION - II



CALCULATION

Volume of NaOH (V 1) = ------------------- ml ( titre value)
Strength of NaOH (N 1) = ------------------- N
Volume of HCl (V 2) = ------------------ml
Strength of HCl (N 2) = ------------------ N
N 2 = V 1 N 1 / V 2
Strength of HCl = -------------------- N
Amount of HCl present in 1000ml of the given solution = Strength x equivalent weight of HCl
= ------------------ X 36.5
= --------------------- g
S.No Volume of
NaOH (ml)
pH
11

12

13

14

15

16

17

18

19

20

S.No
Volume of
NaOH (ml)
pH ?pH ?V ?pH / ?V
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
27



Now NaOH is gradually added from the burette to HCl taken in the beaker. pH of the solution is noted for
each addition of NaOH. This process is continued until 5 readings are taken after the end point.
A fair titration is performed to find the exact end point.





RESULT

(i) Strength of the given HCl solution = ---------------- N
(ii) Amount of HCl present in a litre of the solution = ---------------- g


VIVA-VOCE

1. What is meant by pH?
2. What is the name of the reference electrode used ?
3. Why does pH value increase suddenly at the end point?
4. What is the indicator used in the titration?
5. What is the pH range of human blood?
6. What is the unit of pH?
7. How will you calculate the amount of HCl?
8. How is glass electrode represented?
9. Why is glass electrode known as ion selective electrode?
10. What is the chemical reaction involved in this titration?





28




SHORT PROCEDURE


CONTENTS
TITRATION
Burette solution

Std Sodium Hydroxide

Pipette solution

20 ml mixture of acid (HCl+ CH 3COOH)


Additional solution

20 ml distilled water


End point

Conductivity decreases-slowly increases-Sudden increase



Equivalent Weight of HCl = 36.5


Equivalent Weight of CH 3COOH = 60



MODEL GRAPH


Conductance
Volume of NaOH
Mixture of Acids






29




Expt. No. 5 CONDUCTOMETRIC TITRATION OF MIXTURE
OF ACIDS

AIM
To determine the amount of a strong acid and a weak acid present in the given solution.

PRINCIPLE

Solution of electrolytes conducts electricity due to the presence of ions. Since specific conductance of a
solution is proportional to the concentration of ions in it, conductance of the solution is measured during the titration.

HCl + NaOH ? NaCl + H 2O (I neutralization)

CH 3COOH + NaOH ? CH 3COONa + H 2O (II neutralization)

When a solution of HCl is treated with NaOH the fast moving hydrogen ions are progressively replaced by
slow moving sodium ions. As a result conductance of the solution decreases. This decrease will take place until the
first neutralisation point is reached. Further addition of alkali results in formation of sodium acetate.

Since sodium acetate is stronger than acetic acid conductivity slowly increases until all acetic acid is
completely neutralized.(II Neutralisation) This is due to the presence of fast moving OH
-
ions. Anymore addition of
alkali increases the conductance sharply.

PROCEDURE
The burette is filled with NaOH solution upto zero mark. The given unknown solution (mixture of a weak &
a strong acid) is transferred into a 100ml standard flask and made upto the mark with distilled water. 20ml of the
made up solution is pipetted out into a clean 100ml beaker. The solution is diluted to 20ml using distilled water. A
conductivity cell is dipped into the solution and the terminals are connected to a conductivity meter.
30


TITRATION


CALCULATION OF STRENGTH OF HCl
Volume of NaOH (V 1) = --------------- ml (titre value)
Strength of NaOH (N 1) = ---------------- N
Volume of HCl (V 2) = ------------ ml
Strength of HCl (N 2) = -------------- N

N 2 = V 1 N 1 / V 2
Strength of HCl = ---------------- N
CALCULATION OF STRENGTH OF CH3COOH
Volume of NaOH (V 1) = ------------ ml (titre value)
Strength of NaOH (N 1) = ------------ N
Volume of CH 3COOH (V 2) = ------------ ml
Strength of CH 3COOH (N 2) = ------------ N
N 2 = V 1 N 1 / V 2

Strength of CH 3COOH = ------------ N



S.No

Volume of NaOH
(ml)

Conductance (mho)

14

15

16

17
18
19
20

21
22
23
24
25
26

S.No

Volume of NaOH
(ml)

Conductance (mho)

1
2
3
4
5
6
7
8
9
10
11
12
13
31

The burette solution is added to the unknown solution in the beaker in 0.5 ml increments, the solution is
stirred using a glass rod, and the observed conductance values are read from the meter. The conductance values
show decrease in the initial values, then gradually increases and finally shows a steep increase. The titration hence
shows two end-points (i.e) I neutralization (weak acid) & II neutralization (strong acid).
The accurate end-point is obtained by plotting a graph between observed conductance Vs volume of
NaOH added.

RESULT
The strength of acids present in the given unknown solution are:
a) Strong acid = ---------------- N
b) Weak acid = -----------------N



VIVA-VOCE

1. What is weak acid?
2. How many end points are obtained from the graph? Comment two end points.
3. Why is the conductance increase in the first end point?
4. What mixture of acids used in this titration?
5. Write the neutralization reaction between CH 3COOH and NaOH.
6. What is the solution present in the conductivity cell?
7. What are strong and weak electrolytes?
8. Give an example for strong acid and weak acid.
9. What is the strong electrolyte of weak electrolyte?
10. Give an example for strong base.









32

SHORT PROCEDURE



















ROUGH GRAPH







EMF(mV)






Volume of Potassium dichromate (ml)

FAIR GRAPH









? E / ? V

Volume of Potassium dichromate (ml)




CONTENTS

TITRATION I

TITRATION II
Burette solution

Std Potassium dichromate

Std Potassium dichromate

Pipette solution

10 ml of FAS


10 ml of FAS



Additional
solution

20 ml distilled water+
10 ml of dil H 2SO 4


20 ml distilled water+
10 ml of dil H 2SO 4

End point

Sudden increase in EMF

EMF increases and decreases

Equivalent Weight of Ferrous ion = 55.85

33


Expt. No. 6 ESTIMATION OF FERROUS ION BY POTENTIOMETRIC
TITRATION

AIM
To estimate the amount of ferrous ion present in whole of the given solution potentiometrically. A standard
solution of potassium dichromate of strength -----------N is provided.

PRINCIPLE

Potentiometric titrations depend on measurement of emf between reference electrode and an indicator
electrode. When a solution of ferrous iron is titrated with a solution of potassium dichromate, the following redox
reaction takes place.

6Fe
2+
+ Cr 2O 7
2-
+ 14 H
+
? 6Fe
3+
+ 2Cr
3+
+ 7H 2O

During this titration Fe
2+
is converted in to Fe
3+
, whose concentration increases. At the end point, there
will be a sharp change due to sudden removal of all Fe
2+
ions.
The cell is set up by connecting this redox electrode with a calomel electrode as shown below:

Pt, Fe
2+
, Fe
3+
, II KCl , HgCl 2 (s), Hg

A graph between EMF measured against the volume of potassium dichromate added is drawn and the
end point is noted from the graph.

PROCEDURE

10ml of Ferrous solution is pipetted out into a 100 ml beaker. 10ml of dil.H 2SO 4 and 20ml of distilled water
are added. A platinum electrode and a calomel electrode are dipped into this solution and connected to the
potentiometer. Then 1ml of potassium dichromate is added to the solution and stirred well for 30 seconds. The
EMF is measured and the titration is continued by adding potassium dichromate in 1ml increments till five
measurements after the end point.



34


ROUGH TITRATION



S.No.

Volume of dichromate (ml)

EMF (mV)


1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.





35







A graph is drawn by plotting the emf against the volume of potassium dichromate and the end point range is
fixed.


About 20ml of Ferrous solution is pipetted out and the titration is continued by adding 0.1ml increaments of
potassium dichromate in the end point range. The emf is measured for each 0.1ml after stirring the solution well.


A graph is plotted between emf and the volume of potassium dichromate and also a first derivative graph is
plotted ( ? E/ ? V against vol. of K 2Cr 2O 7). The strength of Ferrous solution and the amount of Ferrous ion present are
calculated from the end point.



























36

FAIR TITRATION

S.No Volume of
Dichromate (ml)
Emf (mV) ?E ?V ?E/?V






















CALCULATION

Volume of Potassim dichromate (V 1) = -------------- ml
Normality of Potassium dichromate (N 1) = --------------- N
Volume of Ferrous sulphate (V 2) = --------------- ml
Normality of Ferrous sulphate (N 2) = --------------- N
Amount of Ferrous ion present in 1000ml of the solution = Normality X Equivalent weight of ferrous ion
= --------------- X 55.85 g

The amount of Ferrous ion present in the given solution = ----------------- g






37









RESULT

The amount of Ferrous ion present in the whole of the given solution = --------------- g.








VIVA-VOCE

1. What is EMF?
2. What is the basic principle of potentiometric titration?
3. Why does EMF increase during the titration?
4. Write the cell representation of the titration.
5. What is redox reaction?
6. What is the purpose of adding sulphuric acid?
7. What are the advantages of potentiometric titration?
8. How will you obtain the end point in the titration?
9. What is the name of the indicator electrode used in this titration?
10. What is the name of the reference electrode used?








38



SHORT PROCEDURE



CONTENTS

TITRATION
Burette solution

Sodium Hydroxide

Pipette solution

20 ml HCl


Additional solution

20 ml distilled water


End point

Decrease in conductance- increase in conductance

Equivalent Weight of HCl = 36.5
















Conductance

Volume of NaOH ( ml)









39


Expt.No. 7 CONDUCTOMETRIC TITRATION OF STRONG ACID
WITH STRONG BASE
AIM

To determine the strength of a strong acid by titrating a strong acid and strong base conductometrically. A
standard solution of NaOH of known strength ---------N is provided.

PRINCIPLE
Solution of electrolytes conducts electricity due to the presence of ions. The specific conductance of a
solution is proportional to the concentration of ions in it. The reaction between HCl and NaOH may be represented
as,
HCl +NaOH ? NaCl + H 2O

When a solution of hydrochloric acid is titrated with NaOH, the fast moving hydrogen ions are
progressively replaced by slow moving sodium ions. As a result conductance of the solution decreases, this
decrease in conductance will take place until the end point is reached. Further addition of alkali raises the
conductance sharply, as there is an excess of hydroxide ions.

A graph is drawn between volume of NaOH added and the conductance of solution. The exact end point
is intersection of the two lines.

PROCEDURE

The given HCl is made up in a 100ml standard flask. 10 ml of this solution is pipetted out in a beaker. The
burette is filled with standard sodium hydroxide upto the mark.

A conductivity cell is dipped into the beaker with HCl solution and connected to the terminals of the
conductivity bridge. About 1ml of STD NaOH is added and stirred well for 30 seconds. The conductance is
measured and the titration is continued till five measurements after the endpoint. A graph is plotted for the
conductance values against the volume of NaOH and the endpoint range is fixed.

40


TABLE



CALCULATION
Volume of Sodium Hydroxide (V 1) = ------------- ml
Normality of Sodium Hydroxide (N 1) = ------------- N
Volume of Strong acid (V 2) = ------------- ml
Normality of Strong acid (N 2) = V 1 N 1
V 2

The strength of the given strong acid = ------------- N




S.NO
Volume of NaOH
(ml)
Conductance
(mho)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
41

The above titration is repeated again and the exact endpoint is found out by adding in increments of 0.1ml
of NaOH in the end point range and continued after endpoint upto five readings.
A graph is plotted with the conductance values against the volume of NaOH and then the strength of the
strong acid is found out.


RESULT

The strength of the given strong acid is found to be = --------------- N







VIVA-VOCE

1. What is the basic principle of conductometric titration?
2. Why is conductance decreased and increased during the titration?
3. What is conductance mention its unit?
4. Give some examples for Strong acids and Strong bases.
5. Write the reaction between HCl and NaOH.
6. What is meant by strong base?
7. Explain why HCl is a strong acid?
8. Explain why the strength of burette solution is always greater than the pipette solution in conductometric
titration.
9. What is the equivalent weight of HCl and NaOH?
10. Write the formula that is used to calculate the amount of HCl.











42

ESTIMATION OF COPPER

Alloy solution Vs Std. Na2S2O3 (Thio) Indicator: Starch

S.No.
Volume of
Alloy Solution
(ml)
Burette Reading (ml) Volume of
Thio
(ml)
Concordant value
(ml)
Initial Final

1.

2.

3.












CALCULATION
Volume of Na 2S 2O 3 V 1 = ------------- ml

Strength of Na 2S 2O 3 N 1 = ------------- N

Volume of brass solution V 2 = ------------- ml

Strength of brass solution N 2 = ------------- ?

= V 1 x N I / /V 2

= -------------

Strength of copper solution is = ------------- N



















43


Expt.No.8 ESTIMATION OF COPPER IN BRASS
AIM
To estimate the amount of copper present in the given sample of brass.

PRINCIPLE
Brass is an alloy with 55% copper and 33% zinc and small amount of lead and aluminum. Brass is dissolved
in conc. nitric acid to convert copper present in the alloy to cupric ions. Then copper is estimated iodometrically by
titrating the iodine that was liberated against standard sodium thio sulphate solution using starch as indicator.

2 Cu
2+
+ 4I
-
? 2 CuI + I2
I 2 + 2 Na 2S 2O 3 ? Na 2S 4O 6 + 2NaI

CHEMICALS REQUIRED
0.1N Potassium dichromate, 0.1N sodium thio sulphate, 0.01M EDTA, Con. HNO 3 , , KI, EBT,
NH 3OH / NH 4Cl buffer, Starch.

PROCEDURE
PREPARATION OF BRASS ALLOY SOLUTION

About 0.2g of the sample of brass was weighed accurately and transferred into a clean dry 250ml beaker. To
this about 10ml of con. Nitric acid was added and allowed to boil for a small interval of time till the alloy was dissolved.
This was cooled, diluted with water and made upto 250 ml in a standard flask.

TITRATION I
STANDARDIZATION OF Na2S2O3 WITH K2Cr2O7 SOLUTION
20ml of the standard potassium dichromate solution is pipetted out into a conical flask. 20ml of dil.sulphuric
acid and 10ml of 10% KI are added. The liberated iodine is titrated against sodium thio sulphate taken in the burette till
the colour changes to yellowish green. 1ml of starch is added till the colour changes from blue to light green colour.
Titration is repeated for concordance.
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?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





3


PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)
1. Fundamentals
To provide students with a solid foundation in Mathematics, Science and fundamentals of engineering,
enabling them to apply, to find solutions for engineering problems and use this knowledge to acquire higher
education
2. Core Competence
To train the students in chemistry practicals so that they apply their knowledge and training to compare,
and to analyze various engineering industrial problems to find solutions
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice this enables
them to find solutions for the real time problems in industry, and to design products
4. Professionalism
To inculcate professional and effective communication skills, leadership qualities and team spirit in the
students to make them multi-faceted personalities and develop their ability to relate engineering issues to
broader social context
5. Lifelong Learning/Ethics
To demonstrate and practice ethical and professional responsibilities in the industry and society in the
large, through commitment and lifelong learning needed for successful professional career






4


PROGRAMME OUTCOMES (POs)
To demonstrate and apply knowledge of Mathematics, Science and engineering fundamentals in the following
experiments.
1 .To estimate HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. To determine total, temporary & permanent hardness of water by EDTA method.
3. To determine DO content of water sample by Winkler?s method.
4. To determine chloride content of water sample by Argentometric method.
5. To estimate copper content of the given solution by Iodometry.
6. To determine strength of given hydrochloric acid using pH meter.
7. To determine strength of acids in a mixture of acids using conductivity meter.
8. To determine iron content of the given solution using potentiometer.
9. To estimate iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. To estimate sodium and potassium present in water using flame photometer.
11. To determine molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. To determine Pseudo first order kinetics ? ester hydrolysis.
13. To determine Corrosion experiment ? weight loss method.
14. To estimate CMC.
15. To estimate Phase change in a solid.
16. To determine strength of strong acid vs strong base using conductivity meter.











5

BS8161 - CHEMISTRY LABORATORY
SYLLABUS


? To make the student to acquire practical skills in the determination of water quality
parameters through volumetric and instrumental analysis.

? ???? ??? ???? ?? ???? ? ? ?To acquaint the students with the determination of molecular weight of a polymer by
viscometery.

LIST OF EXPERIMENTS:
1. Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. Determination of total, temporary & permanent hardness of water by EDTA method.
3. Determination of DO content of water sample by Winkler?s method.
4. Determination of chloride content of water sample by Argentometric method.
5. Estimation of copper content of the given solution by Iodometry.
6. Determination of strength of given hydrochloric acid using pH meter.
7. Determination of strength of acids in a mixture of acids using conductivity meter.
8. Estimation of iron content of the given solution using potentiometer.
9. Estimation of iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. Estimation of sodium and potassium present in water using flame photometer.
11. Determination of molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. Pseudo first order kinetics ? ester hydrolysis.
13. Corrosion experiment ? weight loss method.
14. Determination of CMC.
15. Phase change in a solid.
16. Conductometric titration of strong acid vs strong base.




? The students will be outfitted with hands-on knowledge in the quantitative chemical
analysis of water quality related parameters.
COURSE OBJECTIVES
COURSE OUTCOMES
6


INDEX [ SEMESTER ? I ]


S.No.



Date


Experiment

Date of
submission



Mark


Signature

1.

Estimation of HCl using Na 2CO 3 as
primary standard and Determination of
alkalinity in water sample.



2.


Determination of total, temporary &
permanent hardness of water by EDTA
method.



3.


Determination of chloride content of water
sample by argentometric method.



4.


Determination of strength of given
hydrochloric acid using pH meter.



5.


Determination of strength of acids in a
mixture of acids using conductivity meter.



6.


Estimation of iron content of the given
solution using potentiometer.



7.





Conductometric titration of strong acid Vs
strong base.



8.



Estimation of copper content of the given
solution by Iodometry


9.
Estimation of sodium and potassium
present in water using flame photometer




7




CONTENTS


S.No.


NAME OF EXPERIMENT

PAGE
No.
SEMESTER - I
1.
Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in
water sample.
09
2. Determination of total, temporary & permanent hardness of water by EDTA method. 15
3. Determination of chloride content of water sample by Argentometric method. 21
4. Determination of strength of given hydrochloric acid using pH meter. 25
5. Determination of strength of acids in a mixture of acids using conductivity meter. 29
6. Estimation of iron content of the given solution using potentiometer. 33
7. Conductometric titration of strong acid Vs strong base.

39


42

8


Estimation of copper content of the given solution by Iodometry 43
9 Estimation of sodium and potassium present in water using flame photometer 47






8



SHORT PROCEDURE:

CONTENTS
TITRATION
Estimation of alkalinity in water sample
(Std HCl Vs water sample)

Burette solution

Std. HCl


Pipette solution

Water sample


Indicator


(i) Phenolphthalein
(ii) Methyl orange


End point

(i) Disappearance of pink colour
(ii) Appearance of reddish orange colour






Relationship
between P &M
Nature of alkalinity
Amount of individual
alkalinities
OH
-
HCO 3
-


CO 3
2-

P = M

only OH
-

P or M

?
0.0

0.0


2P = M

only CO 3
2-


2P or M


0.0


0.0


?

P =0, M?0

only HCO 3
-



M



0.0



?

0.0


2P > M


OH
-
&CO 3
2-


OH
-
= 2P-M
CO 3
2-
= 2(M-P)


?

0.0

?

P < ? M




HCO 3
-
&CO 3
2-


HCO 3
-
= M-2P
CO 3
2-
= 2P

0.0 ? ?




9





Expt. No. 1 DETERMINATION OF ALKALINITY IN WATER
AIM
To determine the type and amounts of alkalinity in the given water sample. A standard solution of Na 2CO 3
of strength ____N is given.

PRINCIPLE
Alkalinity in water is due to the presence of soluble hydroxides, bicarbonates and carbonates.
Determination of various types and amounts of alkalinity is easily carried out by titration with standard HCl
employing the indicators phenolphthalein and methyl orange independently or in succession.

The following reactions occur when different types of alkalinity are neutralized with acid.

OH
?
+ H
+
? H 2O completed at pH 8.2-9.0 ----- (1)

CO 3
2 ?
+ H
+
? HCO 3
?
----- (2)

HCO 3
?
+ H
+
? (H 2CO 3) ? H 2O + CO 2, completed at pH 4.2-5.5 ----- (3)

Neutralisation (1) & (2) will be notified by phenolphthalein end-point while all the three will be

accounted by
methyl orange end-point. Bicarbonate in eqn. (3) may be due to the existence of soluble free bicarbonate salts and
bicarbonates resulting from half neutralization of soluble carbonates (eqn. (2))

Various steps to be followed

a) A known volume of water sample is titrated against std. HCl using first phenolphthalein indicator till
end-point (P) and the titration is continued without break using methyl orange indicator till the end-
point (M).



10


Titration

Estimation of Alkalinity in water sample

Standard HCl Vs Water sample Indicator: 1. Phenolphthalein
2. Methyl Orange


S.No.
Volume
of water
sample (ml)
Burette Reading
Concordant value

Initial Phenolphthalein End
Point (P)
Methyl Orange End
Point (M)

1

2






CALCULATION

Hydroxide ion alkalinity
Volume of HCl (2P-M) = ???????ml

Strength of HCl = ???????? N

Volume of water sample = ???????...ml

Strength of water sample = Volume of HCl (2P-M) x Strength of HCl
Volume of water sample

=

? Hydroxide ion alkalinity in terms of
CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ??????.mg/l







11




b) From the magnitudes of the P & M, the nature of alkalinity can be arrived as follows:

(i) P = M => Presence of only OH
-

(ii) 2P = M => Presence of only CO 3
2-

(iii) P =0, M=0 => Presence of only HCO 3
-
(iv) 2P > M => Presence of OH
-
& CO 3
2-
(v) 2P < M => Presence of HCO 3
-
& CO 3
2-

(Mixture of OH
-
& HCO3
-
is not listed since they do not exist together and are considered equivalent to CO 3
2-
).

PROCEDURE
TITRATION
ESTIMATION OF ALKALINITY IN WATER SAMPLE

Exactly 20 ml of water sample is pipetted out into a clean conical flask. Few drops of phenolphthalein
indicator are added and titrated against a standardized HCl taken in the burette. The end point is the
disappearance of pink colour, which is noted as P. Few drops of methyl orange indicator is added to the same
solution. The solution turns to yellow. The titration is continued further by adding same HCl without break till the
end point is reached. The end point is the colour change from yellow to reddish orange.

The experiment is repeated to get concordant values. From the magnitudes of P & M values, the type of
alkalinity present in the water sample is inferred and the individual amounts are calculated and reported.










12


Carbonate ion alkalinity

Volume of HCl 2 (M ? P) = ??? ????????ml

Strength of HCl = ??.?????..???...N

Volume of water sample =........................................ml

Strength of water sample = Volume of HCl 2 (M ? P) x Strength of HCl
Volume of water sample

= ???????????.. N




? Carbonate ion alkalinity
in terms of CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ???????????mg/l

















13





RESULT

1) The type of alkalinity present in the water sample = -------------------------ions.

2) The individual amounts of alkalinity present in the water sample:
Hydroxide ion alkalinity

= ----------------- ppm
Carbonate ion alkalinity = ------------------ ppm
Bicarbonate ion alkalinity = ----------------- ppm





VIVA-VOCE


1. What is meant by alkalinity?
2. What are the ions responsible for alkalinity?
3. Why OH
-
and HCO 3
?
ions cannot exist together in water?
4. What are the ions responsible for alkalinity when 2P > M?
5. What is the pH range for both in acidic and basic solutions?
6. What is the colour of phenolphthalein in an acid and in an alkaline solution?
7. What is the purpose of using two indicators in same titration?
8. What are the possible combinations of ions for alkalinity?
9. How is the amount of alkalinity expressed?
10. What are the types of indicator used in this experiment?







14

SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II TITRATION III
Standardisation of
EDTA
(EDTA Vs Std
Hard water)
Determination of
total hardness
(Std EDTA Vs Hard
water sample)
Determination of
permanent hardness
(Std EDTA Vs Boiled
Hard water sample)

Burette solution

EDTA solution

EDTA solution

EDTA solution

Pipette solution

20ml Std. hard water

20 ml hard water sample

20ml boiled hard water sample

Indicator

2 drops of EBT

2 drops of EBT

2 drops of EBT

Additional soln.


Ammoniacal Buffer
solution (5ml)

Ammoniacal Buffer solution
(5ml)

Ammoniacal Buffer solution
(5ml)
End point Wine - red to Steel blue Wine - red to steel blue Wine - red to Steel blue




STANDARDISATION OF EDTA
Titration - I
Std. HARD WATER Vs EDTA Indicator: EBT

S. No.
Volume of std hard
water (ml)
Burette Reading Volume of
EDTA
(V 1) (ml)
Concordant value

Initial

Final



Volume of std .hard water taken = 20 ml
Volume of EDTA consumed (V 1) = --------------- ml
1 ml of std.hard water = 1mg of CaCO 3
20 ml of std hard water = 20 mg of CaCO 3

V 1 ml of EDTA solution containing 20 mg of CaCO 3
1 ml of EDTA solution = 20 / V 1 mg of CaCO 3
= -----------------------mg of CaCO 3


15

Expt. No. 2 DETERMINATION OF TOTAL, TEMPORARY AND
PERMANENT HARDNESS OF WATER

AIM
To estimate the amount of total, temporary & permanent hardness in the given sample of water.

PRINCIPLE
The estimation is based on the complexometric titration.

(i) Total hardness of water is estimated by titrating against EDTA using EBT indicator.
EBT+M ?[EBT-M] (unstable complex)
(EBT-M) (Unstable complex) +EDTA ? [EDTA-M] (stable complex) +EBT
EBT indicator forms wine- red colored complex with metal ions present in water. On addition of EDTA
metal ions preferably forms complexes with EDTA and steel blue EBT indicator is set free. Therefore
change of colour from wine- red to steel blue denotes the end point.

(ii) Temporary hardness is removed by boiling the water.
Ca (HCO 3) 2 ? CaCO 3 +CO 2 ?+H 2O
Mg (HCO 3) 2 ? Mg(OH) 2 +2CO 2 ?
The precipitate is filtered and the remaining permanent hardness is estimated using EDTA.

PROCEDURE

TITRATION ? I
STANDARDISATION OF EDTA

Pipette out 20ml of standard hard water into a 250ml conical flask. Add 5ml of buffer solution and 3
drops of eriochrome black T indictor. Titrate the solution with EDTA from the burette until the colour
changes from wine- red to steel blue at the end point. Repeat the titration for concordant values. Let the
titre value be V 1ml.


16


Titration-II
SAMPLE HARD WATER Vs Std EDTA Indicator: EBT

S.No. Volume of sample
hard water (ml)
Burette Reading Volume of
EDTA
(V 2) (ml)
Concordant value

Initial

Final




CALCULATION

Calculation of total hardness


Volume of EDTA consumed (V 2) = ------------------------- ml
1ml of EDTA = 20 / V 1 mg of CaCO 3
V 2 ml of EDTA = 20 / V 1 x V 2 mg of CaCO 3

( i.e), If 20ml of sample hard water contains 20 x V 2 mg of CaCO 3 / V 1

Then 1000ml of water sample = 20 x V 2 x 1000 / V 1 x 20 mg of CaCO 3

= 1000 x V 2 / V 1 mg of CaCO3

Total hardness of given water sample = ---------------------ppm









17



DETERMINATION OF TOTAL HARDNESS

Pipette out 20ml of sample hard water into a clean conical flask. Add 5ml of buffer solution and 4 -5
drops of Eriochrome black -T indicator. Titrate the wine - red coloured solution with EDTA from the burette until
the colour steel blue appears at the end point. Repeat the titration for concordant values. Let the titre value be
V 2ml.



DETERMINATION OF PERMANENT HARDNESS

Take 100ml of hard water sample in a 500ml beaker and boil gently for about 1hour. Cool, filter it into a
100ml standard flask and make the volume up to the mark. Take 20ml of this solution and proceed it in the same
way as in titration (I). The volume of EDTA consumed corresponds to the permanent hardness of the water
sample. Let the titre value be V 3ml. Temporary hardness is calculated by subtracting permanent hardness from
total hardness.





















18




DETERMINATION OF PERMANENT HARDNESS
BOILED SAMPLE WATER Vs Std. EDTA Indicator: EBT


S.No.
Volume of boiled
hard water (ml)
Burette Reading (ml) Volume of
EDTA
(ml)

Concordant value

Initial Final



CALCULATION OF PERMANENT HARDNESS


Volume of EDTA consumed V 3 = ---------------------ml

1ml of EDTA = 20 / V 1 mg of CaCO 3

V 3ml of EDTA = 20 / V 1 x V 3 mg of CaCO 3

(i.e) 20 ml of boiled sample hard water = 20 / V 1 x V 3 mg of CaCO 3

Then 1000ml of boiled water sample = 20 / V 1 x V 3 / 20 * 1000mg of CaCO 3

= 1000 x V 3 / V 1 mg of CaCO 3

permanent hardness of boiled water sample = -----------------ppm

Temporary hardness of the given water sample = Total hardness ? Permanent hardness

= ------------------ppm

19







RESULT

(i) Total hardness of the given sample water = -------------- ppm.
(ii) Permanent hardness of the given sample water = --------------- ppm.
(iii) Temporary hardness of the given sample water = ----------------ppm.







VIVA-VOCE

1. Define ? Hard water
2. What is the structure of EDTA?
3. How will you calculate temporary hardness?
4. What is the role of the buffer in EDTA titration?
5. What is the permissible limit of hardness in drinking water?
6. Name the hardness producing ions present in water.
7. Name two salts which are responsible for temporary hardness.
8. Why is CaCO 3 taken as the standard?
9. Write the expansion of EDTA.
10. What is meant by EBT?











20





SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II
Standardisation of
AgNO 3
Estimation of Chloride
Burette solution

AgNO 3 solution

Std. AgNO 3 solution

Pipette solution

20ml std KCl solution

20 ml water sample

Indicator

1ml K 2CrO 4

1ml K 2CrO 4


End point

yellow to reddish brown

yellow to reddish brown

Titration I
Std. AgNO3 Vs KCl Indicator: Potassium Chromate













CALCULATION

Volume of KCl (V 1) = ------- ml

Strength of KCl (N 1) = ------- N

Volume of Silver Nitrate (V 2) = -------- ml

Strength of Siver Nitrate V 1N 1
N 2 =
V 1

= --------------------- N

S.No.
Volume of KCl
(ml)
Burette Reading (ml)
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

21




Expt.No. 3 ESTIMATION OF CHLORIDE CONTENT IN WATER
(ARGENTOMETRIC METHOD)
AIM
To estimate the amount of chloride present in given water sample by Argentometric method (Mohr?s
method). You are provided with standard solution of NaCl of strength --------N and a approximately N/10 solution of
Silver nitrate.

PRINCIPLE
The Chloride ion in the form of NaCl, KCl, CaCl 2, MgCl 2 etc., present in the water sample can be estimated
by Argentometric method or known as Mohr?s method. It is an example for precipitation titration. The reaction
between std. Sodium chloride and Silver nitrate is given below.
AgNO 3 + NaCl ? AgCl ? + NaNO 3
The completion of reaction can be observed by employing potassium chromate as the indicator. The end
point is the colour change from yellow to reddish brown due to the following reaction.
2AgNO 3 + K 2CrO 4 ? Ag 2CrO 4 ? + 2KNO 3
Potassium chromate indicator will not be precipitated as silver chromate until all the chlorides in the solution
have been precipitated as AgCl Since a precipitation reaction takes place in preference, this reaction takes place
only at the end point.

PROCEDURE
TITRATION I: STANDARDISATION OF SILVER NITRATE
Pipette out 20ml of standard sodium or potassium chloride solution into a clean conical flask. Add 1ml of 5%
K 2CrO 4 indicator, as the solution turns yellow in colour. Titrate it against silver nitrate solution taken in the burette.
Observe the nearness of the end point through the formation of coagulated silver chloride precipitate at the bottom
of the flask. Now add the silver nitrate drop by drop until the solution gets a faint reddish brown tinge. Repeat the
titration for concordant value. Let the volume of silver nitrate be V 2ml.





22






TITRATION - II

Std AgNO3 Vs WATER SAMPLE Indicator: Potassium Chromate













CALCULATION

Volume of Silver Nitrate (V 3) = ------------ ml

Strength of Siver Nitrate (N 3) = ------------- N

Volume of Water sample (V 4) = -------------- ml

Strength of Water sample V 3 N 3
(N 4) =
V 4

= ----------------- N

Amount of Chloride ion present in 1000 ml of the water sample = Equivalent mass of HCl X 1000


= N 4 x 35.46 x 1000


= -----------------mg/l







S.No.
Volume of water
sample (ml)
Burette Reading
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

23





TITRATION - II
ESTIMATION OF CHLORIDE ION

Pipette out 40 ml of the given water sample into a clean conical flask.To this sample add 1ml of 5% K 2CrO 4
indicator and titrate it against the standardized silver nitrate solution taken in the burette and continue the titration
until the solution produces a reddish brown colour. Note down the end point and repeat the titration for
concordance. Let the volume be V 3ml.







RESULT

The amount of chloride ion present in the water sample = ----------------- mg/l.




VIVA-VOCE

1. Why is this method known as Argentometric method?
2.
What is the chemical reaction between AgNO 3 and Cl
-
ions present in water?

3.
What is the form of Chloride ion present in water?

4. What is the reaction between AgNO 3 and K 2CrO 4 ?
5. What is the name of the method used in this titration?
6. Name the link solution used in the determination.
7. Name the solution used to standardize AgNO 3.
8. What is the indicator used in the determination?
9. How will you calculate the amount of chloride ion in the given solution?
10. What is the colour change in the titration?




24




SHORT PROCEDURE


CONTENTS

TITRATION I

TITRATION II
Burette solution

Std Sodium Hydroxide

Std Sodium Hydroxide

Pipette solution

20 ml hydrochloric acid 20 ml hydrochloric acid
Additional solution


20 ml distilled water

20 ml distilled water


End point



Sudden increase in pH
pH gradual increase

Equivalent Weight of HCl = 36.5







ROUGH GRAPH FAIR GRAPH











pH
? pH/ ? V





Volume of NaOH
(ml)
Volume of NaOH
(ml)





25



Expt. No. 4 DETERMINATION OF STRENGTH OF HCl by pH METRY

AIM
To determine the strength of given HCl by pH metry. A standard solution of 0.1N NaOH is provided.

PRINCIPLE
The pH of a solution is related to H
+
ion concentration by the following formula.

. pH = -log [ H
+
]

pH of a solution is indirectly related to H
+
ion concentration. When NaOH is added slowly to HCl, H
+
ions
get neutralized by OH
-
ions. The pH increases slowly.

H
+
+ Cl
-
+ Na
+
+ OH
-
? Na
+
+ Cl
-
+H 2O

When all H
+
ions of HCl are neutralized at the end point, addition of NaOH causes high increase in pH
because of the addition of excess OH
-
ions.

MATERIALS REQUIRED
pH meter, Glass electrode, Burette, Pipette, Std.NaOH, approximately N/10 HCl .

PROCEDURE

The burette is washed with distilled water, rinsed with the given std. Sodium hydroxide and filled with the
same solution. Exactly 10ml of the given HCl solution is pipetted out into a clean beaker. It is then diluted to 50ml
with distilled water. A glass electrode is dipped into the solution and its terminals are connected to a pH meter.

26

TITRATION - I
S.No Volume of
NaOH (ml)
pH
1

2

3

4

5

6

7

8

9

10


TITRATION - II



CALCULATION

Volume of NaOH (V 1) = ------------------- ml ( titre value)
Strength of NaOH (N 1) = ------------------- N
Volume of HCl (V 2) = ------------------ml
Strength of HCl (N 2) = ------------------ N
N 2 = V 1 N 1 / V 2
Strength of HCl = -------------------- N
Amount of HCl present in 1000ml of the given solution = Strength x equivalent weight of HCl
= ------------------ X 36.5
= --------------------- g
S.No Volume of
NaOH (ml)
pH
11

12

13

14

15

16

17

18

19

20

S.No
Volume of
NaOH (ml)
pH ?pH ?V ?pH / ?V
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
27



Now NaOH is gradually added from the burette to HCl taken in the beaker. pH of the solution is noted for
each addition of NaOH. This process is continued until 5 readings are taken after the end point.
A fair titration is performed to find the exact end point.





RESULT

(i) Strength of the given HCl solution = ---------------- N
(ii) Amount of HCl present in a litre of the solution = ---------------- g


VIVA-VOCE

1. What is meant by pH?
2. What is the name of the reference electrode used ?
3. Why does pH value increase suddenly at the end point?
4. What is the indicator used in the titration?
5. What is the pH range of human blood?
6. What is the unit of pH?
7. How will you calculate the amount of HCl?
8. How is glass electrode represented?
9. Why is glass electrode known as ion selective electrode?
10. What is the chemical reaction involved in this titration?





28




SHORT PROCEDURE


CONTENTS
TITRATION
Burette solution

Std Sodium Hydroxide

Pipette solution

20 ml mixture of acid (HCl+ CH 3COOH)


Additional solution

20 ml distilled water


End point

Conductivity decreases-slowly increases-Sudden increase



Equivalent Weight of HCl = 36.5


Equivalent Weight of CH 3COOH = 60



MODEL GRAPH


Conductance
Volume of NaOH
Mixture of Acids






29




Expt. No. 5 CONDUCTOMETRIC TITRATION OF MIXTURE
OF ACIDS

AIM
To determine the amount of a strong acid and a weak acid present in the given solution.

PRINCIPLE

Solution of electrolytes conducts electricity due to the presence of ions. Since specific conductance of a
solution is proportional to the concentration of ions in it, conductance of the solution is measured during the titration.

HCl + NaOH ? NaCl + H 2O (I neutralization)

CH 3COOH + NaOH ? CH 3COONa + H 2O (II neutralization)

When a solution of HCl is treated with NaOH the fast moving hydrogen ions are progressively replaced by
slow moving sodium ions. As a result conductance of the solution decreases. This decrease will take place until the
first neutralisation point is reached. Further addition of alkali results in formation of sodium acetate.

Since sodium acetate is stronger than acetic acid conductivity slowly increases until all acetic acid is
completely neutralized.(II Neutralisation) This is due to the presence of fast moving OH
-
ions. Anymore addition of
alkali increases the conductance sharply.

PROCEDURE
The burette is filled with NaOH solution upto zero mark. The given unknown solution (mixture of a weak &
a strong acid) is transferred into a 100ml standard flask and made upto the mark with distilled water. 20ml of the
made up solution is pipetted out into a clean 100ml beaker. The solution is diluted to 20ml using distilled water. A
conductivity cell is dipped into the solution and the terminals are connected to a conductivity meter.
30


TITRATION


CALCULATION OF STRENGTH OF HCl
Volume of NaOH (V 1) = --------------- ml (titre value)
Strength of NaOH (N 1) = ---------------- N
Volume of HCl (V 2) = ------------ ml
Strength of HCl (N 2) = -------------- N

N 2 = V 1 N 1 / V 2
Strength of HCl = ---------------- N
CALCULATION OF STRENGTH OF CH3COOH
Volume of NaOH (V 1) = ------------ ml (titre value)
Strength of NaOH (N 1) = ------------ N
Volume of CH 3COOH (V 2) = ------------ ml
Strength of CH 3COOH (N 2) = ------------ N
N 2 = V 1 N 1 / V 2

Strength of CH 3COOH = ------------ N



S.No

Volume of NaOH
(ml)

Conductance (mho)

14

15

16

17
18
19
20

21
22
23
24
25
26

S.No

Volume of NaOH
(ml)

Conductance (mho)

1
2
3
4
5
6
7
8
9
10
11
12
13
31

The burette solution is added to the unknown solution in the beaker in 0.5 ml increments, the solution is
stirred using a glass rod, and the observed conductance values are read from the meter. The conductance values
show decrease in the initial values, then gradually increases and finally shows a steep increase. The titration hence
shows two end-points (i.e) I neutralization (weak acid) & II neutralization (strong acid).
The accurate end-point is obtained by plotting a graph between observed conductance Vs volume of
NaOH added.

RESULT
The strength of acids present in the given unknown solution are:
a) Strong acid = ---------------- N
b) Weak acid = -----------------N



VIVA-VOCE

1. What is weak acid?
2. How many end points are obtained from the graph? Comment two end points.
3. Why is the conductance increase in the first end point?
4. What mixture of acids used in this titration?
5. Write the neutralization reaction between CH 3COOH and NaOH.
6. What is the solution present in the conductivity cell?
7. What are strong and weak electrolytes?
8. Give an example for strong acid and weak acid.
9. What is the strong electrolyte of weak electrolyte?
10. Give an example for strong base.









32

SHORT PROCEDURE



















ROUGH GRAPH







EMF(mV)






Volume of Potassium dichromate (ml)

FAIR GRAPH









? E / ? V

Volume of Potassium dichromate (ml)




CONTENTS

TITRATION I

TITRATION II
Burette solution

Std Potassium dichromate

Std Potassium dichromate

Pipette solution

10 ml of FAS


10 ml of FAS



Additional
solution

20 ml distilled water+
10 ml of dil H 2SO 4


20 ml distilled water+
10 ml of dil H 2SO 4

End point

Sudden increase in EMF

EMF increases and decreases

Equivalent Weight of Ferrous ion = 55.85

33


Expt. No. 6 ESTIMATION OF FERROUS ION BY POTENTIOMETRIC
TITRATION

AIM
To estimate the amount of ferrous ion present in whole of the given solution potentiometrically. A standard
solution of potassium dichromate of strength -----------N is provided.

PRINCIPLE

Potentiometric titrations depend on measurement of emf between reference electrode and an indicator
electrode. When a solution of ferrous iron is titrated with a solution of potassium dichromate, the following redox
reaction takes place.

6Fe
2+
+ Cr 2O 7
2-
+ 14 H
+
? 6Fe
3+
+ 2Cr
3+
+ 7H 2O

During this titration Fe
2+
is converted in to Fe
3+
, whose concentration increases. At the end point, there
will be a sharp change due to sudden removal of all Fe
2+
ions.
The cell is set up by connecting this redox electrode with a calomel electrode as shown below:

Pt, Fe
2+
, Fe
3+
, II KCl , HgCl 2 (s), Hg

A graph between EMF measured against the volume of potassium dichromate added is drawn and the
end point is noted from the graph.

PROCEDURE

10ml of Ferrous solution is pipetted out into a 100 ml beaker. 10ml of dil.H 2SO 4 and 20ml of distilled water
are added. A platinum electrode and a calomel electrode are dipped into this solution and connected to the
potentiometer. Then 1ml of potassium dichromate is added to the solution and stirred well for 30 seconds. The
EMF is measured and the titration is continued by adding potassium dichromate in 1ml increments till five
measurements after the end point.



34


ROUGH TITRATION



S.No.

Volume of dichromate (ml)

EMF (mV)


1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.





35







A graph is drawn by plotting the emf against the volume of potassium dichromate and the end point range is
fixed.


About 20ml of Ferrous solution is pipetted out and the titration is continued by adding 0.1ml increaments of
potassium dichromate in the end point range. The emf is measured for each 0.1ml after stirring the solution well.


A graph is plotted between emf and the volume of potassium dichromate and also a first derivative graph is
plotted ( ? E/ ? V against vol. of K 2Cr 2O 7). The strength of Ferrous solution and the amount of Ferrous ion present are
calculated from the end point.



























36

FAIR TITRATION

S.No Volume of
Dichromate (ml)
Emf (mV) ?E ?V ?E/?V






















CALCULATION

Volume of Potassim dichromate (V 1) = -------------- ml
Normality of Potassium dichromate (N 1) = --------------- N
Volume of Ferrous sulphate (V 2) = --------------- ml
Normality of Ferrous sulphate (N 2) = --------------- N
Amount of Ferrous ion present in 1000ml of the solution = Normality X Equivalent weight of ferrous ion
= --------------- X 55.85 g

The amount of Ferrous ion present in the given solution = ----------------- g






37









RESULT

The amount of Ferrous ion present in the whole of the given solution = --------------- g.








VIVA-VOCE

1. What is EMF?
2. What is the basic principle of potentiometric titration?
3. Why does EMF increase during the titration?
4. Write the cell representation of the titration.
5. What is redox reaction?
6. What is the purpose of adding sulphuric acid?
7. What are the advantages of potentiometric titration?
8. How will you obtain the end point in the titration?
9. What is the name of the indicator electrode used in this titration?
10. What is the name of the reference electrode used?








38



SHORT PROCEDURE



CONTENTS

TITRATION
Burette solution

Sodium Hydroxide

Pipette solution

20 ml HCl


Additional solution

20 ml distilled water


End point

Decrease in conductance- increase in conductance

Equivalent Weight of HCl = 36.5
















Conductance

Volume of NaOH ( ml)









39


Expt.No. 7 CONDUCTOMETRIC TITRATION OF STRONG ACID
WITH STRONG BASE
AIM

To determine the strength of a strong acid by titrating a strong acid and strong base conductometrically. A
standard solution of NaOH of known strength ---------N is provided.

PRINCIPLE
Solution of electrolytes conducts electricity due to the presence of ions. The specific conductance of a
solution is proportional to the concentration of ions in it. The reaction between HCl and NaOH may be represented
as,
HCl +NaOH ? NaCl + H 2O

When a solution of hydrochloric acid is titrated with NaOH, the fast moving hydrogen ions are
progressively replaced by slow moving sodium ions. As a result conductance of the solution decreases, this
decrease in conductance will take place until the end point is reached. Further addition of alkali raises the
conductance sharply, as there is an excess of hydroxide ions.

A graph is drawn between volume of NaOH added and the conductance of solution. The exact end point
is intersection of the two lines.

PROCEDURE

The given HCl is made up in a 100ml standard flask. 10 ml of this solution is pipetted out in a beaker. The
burette is filled with standard sodium hydroxide upto the mark.

A conductivity cell is dipped into the beaker with HCl solution and connected to the terminals of the
conductivity bridge. About 1ml of STD NaOH is added and stirred well for 30 seconds. The conductance is
measured and the titration is continued till five measurements after the endpoint. A graph is plotted for the
conductance values against the volume of NaOH and the endpoint range is fixed.

40


TABLE



CALCULATION
Volume of Sodium Hydroxide (V 1) = ------------- ml
Normality of Sodium Hydroxide (N 1) = ------------- N
Volume of Strong acid (V 2) = ------------- ml
Normality of Strong acid (N 2) = V 1 N 1
V 2

The strength of the given strong acid = ------------- N




S.NO
Volume of NaOH
(ml)
Conductance
(mho)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
41

The above titration is repeated again and the exact endpoint is found out by adding in increments of 0.1ml
of NaOH in the end point range and continued after endpoint upto five readings.
A graph is plotted with the conductance values against the volume of NaOH and then the strength of the
strong acid is found out.


RESULT

The strength of the given strong acid is found to be = --------------- N







VIVA-VOCE

1. What is the basic principle of conductometric titration?
2. Why is conductance decreased and increased during the titration?
3. What is conductance mention its unit?
4. Give some examples for Strong acids and Strong bases.
5. Write the reaction between HCl and NaOH.
6. What is meant by strong base?
7. Explain why HCl is a strong acid?
8. Explain why the strength of burette solution is always greater than the pipette solution in conductometric
titration.
9. What is the equivalent weight of HCl and NaOH?
10. Write the formula that is used to calculate the amount of HCl.











42

ESTIMATION OF COPPER

Alloy solution Vs Std. Na2S2O3 (Thio) Indicator: Starch

S.No.
Volume of
Alloy Solution
(ml)
Burette Reading (ml) Volume of
Thio
(ml)
Concordant value
(ml)
Initial Final

1.

2.

3.












CALCULATION
Volume of Na 2S 2O 3 V 1 = ------------- ml

Strength of Na 2S 2O 3 N 1 = ------------- N

Volume of brass solution V 2 = ------------- ml

Strength of brass solution N 2 = ------------- ?

= V 1 x N I / /V 2

= -------------

Strength of copper solution is = ------------- N



















43


Expt.No.8 ESTIMATION OF COPPER IN BRASS
AIM
To estimate the amount of copper present in the given sample of brass.

PRINCIPLE
Brass is an alloy with 55% copper and 33% zinc and small amount of lead and aluminum. Brass is dissolved
in conc. nitric acid to convert copper present in the alloy to cupric ions. Then copper is estimated iodometrically by
titrating the iodine that was liberated against standard sodium thio sulphate solution using starch as indicator.

2 Cu
2+
+ 4I
-
? 2 CuI + I2
I 2 + 2 Na 2S 2O 3 ? Na 2S 4O 6 + 2NaI

CHEMICALS REQUIRED
0.1N Potassium dichromate, 0.1N sodium thio sulphate, 0.01M EDTA, Con. HNO 3 , , KI, EBT,
NH 3OH / NH 4Cl buffer, Starch.

PROCEDURE
PREPARATION OF BRASS ALLOY SOLUTION

About 0.2g of the sample of brass was weighed accurately and transferred into a clean dry 250ml beaker. To
this about 10ml of con. Nitric acid was added and allowed to boil for a small interval of time till the alloy was dissolved.
This was cooled, diluted with water and made upto 250 ml in a standard flask.

TITRATION I
STANDARDIZATION OF Na2S2O3 WITH K2Cr2O7 SOLUTION
20ml of the standard potassium dichromate solution is pipetted out into a conical flask. 20ml of dil.sulphuric
acid and 10ml of 10% KI are added. The liberated iodine is titrated against sodium thio sulphate taken in the burette till
the colour changes to yellowish green. 1ml of starch is added till the colour changes from blue to light green colour.
Titration is repeated for concordance.
44



CALCULATION


Amount of copper in 1lt of given brass solution = Strength of solution x Eq. Wt of Cu


= ------------------ N x 63.5

= -------------------------

So, Amount of copper in 100ml of given brass solution = ------------------- N x 63.5 x 100 / 1000



ie, ------------g of brass contains = -------------------- g of copper


therefore, % of copper in the given brass sample = ------------------- g x 100


= ------------------ g of brass


= ------------------------ %























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?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





3


PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)
1. Fundamentals
To provide students with a solid foundation in Mathematics, Science and fundamentals of engineering,
enabling them to apply, to find solutions for engineering problems and use this knowledge to acquire higher
education
2. Core Competence
To train the students in chemistry practicals so that they apply their knowledge and training to compare,
and to analyze various engineering industrial problems to find solutions
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice this enables
them to find solutions for the real time problems in industry, and to design products
4. Professionalism
To inculcate professional and effective communication skills, leadership qualities and team spirit in the
students to make them multi-faceted personalities and develop their ability to relate engineering issues to
broader social context
5. Lifelong Learning/Ethics
To demonstrate and practice ethical and professional responsibilities in the industry and society in the
large, through commitment and lifelong learning needed for successful professional career






4


PROGRAMME OUTCOMES (POs)
To demonstrate and apply knowledge of Mathematics, Science and engineering fundamentals in the following
experiments.
1 .To estimate HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. To determine total, temporary & permanent hardness of water by EDTA method.
3. To determine DO content of water sample by Winkler?s method.
4. To determine chloride content of water sample by Argentometric method.
5. To estimate copper content of the given solution by Iodometry.
6. To determine strength of given hydrochloric acid using pH meter.
7. To determine strength of acids in a mixture of acids using conductivity meter.
8. To determine iron content of the given solution using potentiometer.
9. To estimate iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. To estimate sodium and potassium present in water using flame photometer.
11. To determine molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. To determine Pseudo first order kinetics ? ester hydrolysis.
13. To determine Corrosion experiment ? weight loss method.
14. To estimate CMC.
15. To estimate Phase change in a solid.
16. To determine strength of strong acid vs strong base using conductivity meter.











5

BS8161 - CHEMISTRY LABORATORY
SYLLABUS


? To make the student to acquire practical skills in the determination of water quality
parameters through volumetric and instrumental analysis.

? ???? ??? ???? ?? ???? ? ? ?To acquaint the students with the determination of molecular weight of a polymer by
viscometery.

LIST OF EXPERIMENTS:
1. Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. Determination of total, temporary & permanent hardness of water by EDTA method.
3. Determination of DO content of water sample by Winkler?s method.
4. Determination of chloride content of water sample by Argentometric method.
5. Estimation of copper content of the given solution by Iodometry.
6. Determination of strength of given hydrochloric acid using pH meter.
7. Determination of strength of acids in a mixture of acids using conductivity meter.
8. Estimation of iron content of the given solution using potentiometer.
9. Estimation of iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. Estimation of sodium and potassium present in water using flame photometer.
11. Determination of molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. Pseudo first order kinetics ? ester hydrolysis.
13. Corrosion experiment ? weight loss method.
14. Determination of CMC.
15. Phase change in a solid.
16. Conductometric titration of strong acid vs strong base.




? The students will be outfitted with hands-on knowledge in the quantitative chemical
analysis of water quality related parameters.
COURSE OBJECTIVES
COURSE OUTCOMES
6


INDEX [ SEMESTER ? I ]


S.No.



Date


Experiment

Date of
submission



Mark


Signature

1.

Estimation of HCl using Na 2CO 3 as
primary standard and Determination of
alkalinity in water sample.



2.


Determination of total, temporary &
permanent hardness of water by EDTA
method.



3.


Determination of chloride content of water
sample by argentometric method.



4.


Determination of strength of given
hydrochloric acid using pH meter.



5.


Determination of strength of acids in a
mixture of acids using conductivity meter.



6.


Estimation of iron content of the given
solution using potentiometer.



7.





Conductometric titration of strong acid Vs
strong base.



8.



Estimation of copper content of the given
solution by Iodometry


9.
Estimation of sodium and potassium
present in water using flame photometer




7




CONTENTS


S.No.


NAME OF EXPERIMENT

PAGE
No.
SEMESTER - I
1.
Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in
water sample.
09
2. Determination of total, temporary & permanent hardness of water by EDTA method. 15
3. Determination of chloride content of water sample by Argentometric method. 21
4. Determination of strength of given hydrochloric acid using pH meter. 25
5. Determination of strength of acids in a mixture of acids using conductivity meter. 29
6. Estimation of iron content of the given solution using potentiometer. 33
7. Conductometric titration of strong acid Vs strong base.

39


42

8


Estimation of copper content of the given solution by Iodometry 43
9 Estimation of sodium and potassium present in water using flame photometer 47






8



SHORT PROCEDURE:

CONTENTS
TITRATION
Estimation of alkalinity in water sample
(Std HCl Vs water sample)

Burette solution

Std. HCl


Pipette solution

Water sample


Indicator


(i) Phenolphthalein
(ii) Methyl orange


End point

(i) Disappearance of pink colour
(ii) Appearance of reddish orange colour






Relationship
between P &M
Nature of alkalinity
Amount of individual
alkalinities
OH
-
HCO 3
-


CO 3
2-

P = M

only OH
-

P or M

?
0.0

0.0


2P = M

only CO 3
2-


2P or M


0.0


0.0


?

P =0, M?0

only HCO 3
-



M



0.0



?

0.0


2P > M


OH
-
&CO 3
2-


OH
-
= 2P-M
CO 3
2-
= 2(M-P)


?

0.0

?

P < ? M




HCO 3
-
&CO 3
2-


HCO 3
-
= M-2P
CO 3
2-
= 2P

0.0 ? ?




9





Expt. No. 1 DETERMINATION OF ALKALINITY IN WATER
AIM
To determine the type and amounts of alkalinity in the given water sample. A standard solution of Na 2CO 3
of strength ____N is given.

PRINCIPLE
Alkalinity in water is due to the presence of soluble hydroxides, bicarbonates and carbonates.
Determination of various types and amounts of alkalinity is easily carried out by titration with standard HCl
employing the indicators phenolphthalein and methyl orange independently or in succession.

The following reactions occur when different types of alkalinity are neutralized with acid.

OH
?
+ H
+
? H 2O completed at pH 8.2-9.0 ----- (1)

CO 3
2 ?
+ H
+
? HCO 3
?
----- (2)

HCO 3
?
+ H
+
? (H 2CO 3) ? H 2O + CO 2, completed at pH 4.2-5.5 ----- (3)

Neutralisation (1) & (2) will be notified by phenolphthalein end-point while all the three will be

accounted by
methyl orange end-point. Bicarbonate in eqn. (3) may be due to the existence of soluble free bicarbonate salts and
bicarbonates resulting from half neutralization of soluble carbonates (eqn. (2))

Various steps to be followed

a) A known volume of water sample is titrated against std. HCl using first phenolphthalein indicator till
end-point (P) and the titration is continued without break using methyl orange indicator till the end-
point (M).



10


Titration

Estimation of Alkalinity in water sample

Standard HCl Vs Water sample Indicator: 1. Phenolphthalein
2. Methyl Orange


S.No.
Volume
of water
sample (ml)
Burette Reading
Concordant value

Initial Phenolphthalein End
Point (P)
Methyl Orange End
Point (M)

1

2






CALCULATION

Hydroxide ion alkalinity
Volume of HCl (2P-M) = ???????ml

Strength of HCl = ???????? N

Volume of water sample = ???????...ml

Strength of water sample = Volume of HCl (2P-M) x Strength of HCl
Volume of water sample

=

? Hydroxide ion alkalinity in terms of
CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ??????.mg/l







11




b) From the magnitudes of the P & M, the nature of alkalinity can be arrived as follows:

(i) P = M => Presence of only OH
-

(ii) 2P = M => Presence of only CO 3
2-

(iii) P =0, M=0 => Presence of only HCO 3
-
(iv) 2P > M => Presence of OH
-
& CO 3
2-
(v) 2P < M => Presence of HCO 3
-
& CO 3
2-

(Mixture of OH
-
& HCO3
-
is not listed since they do not exist together and are considered equivalent to CO 3
2-
).

PROCEDURE
TITRATION
ESTIMATION OF ALKALINITY IN WATER SAMPLE

Exactly 20 ml of water sample is pipetted out into a clean conical flask. Few drops of phenolphthalein
indicator are added and titrated against a standardized HCl taken in the burette. The end point is the
disappearance of pink colour, which is noted as P. Few drops of methyl orange indicator is added to the same
solution. The solution turns to yellow. The titration is continued further by adding same HCl without break till the
end point is reached. The end point is the colour change from yellow to reddish orange.

The experiment is repeated to get concordant values. From the magnitudes of P & M values, the type of
alkalinity present in the water sample is inferred and the individual amounts are calculated and reported.










12


Carbonate ion alkalinity

Volume of HCl 2 (M ? P) = ??? ????????ml

Strength of HCl = ??.?????..???...N

Volume of water sample =........................................ml

Strength of water sample = Volume of HCl 2 (M ? P) x Strength of HCl
Volume of water sample

= ???????????.. N




? Carbonate ion alkalinity
in terms of CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ???????????mg/l

















13





RESULT

1) The type of alkalinity present in the water sample = -------------------------ions.

2) The individual amounts of alkalinity present in the water sample:
Hydroxide ion alkalinity

= ----------------- ppm
Carbonate ion alkalinity = ------------------ ppm
Bicarbonate ion alkalinity = ----------------- ppm





VIVA-VOCE


1. What is meant by alkalinity?
2. What are the ions responsible for alkalinity?
3. Why OH
-
and HCO 3
?
ions cannot exist together in water?
4. What are the ions responsible for alkalinity when 2P > M?
5. What is the pH range for both in acidic and basic solutions?
6. What is the colour of phenolphthalein in an acid and in an alkaline solution?
7. What is the purpose of using two indicators in same titration?
8. What are the possible combinations of ions for alkalinity?
9. How is the amount of alkalinity expressed?
10. What are the types of indicator used in this experiment?







14

SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II TITRATION III
Standardisation of
EDTA
(EDTA Vs Std
Hard water)
Determination of
total hardness
(Std EDTA Vs Hard
water sample)
Determination of
permanent hardness
(Std EDTA Vs Boiled
Hard water sample)

Burette solution

EDTA solution

EDTA solution

EDTA solution

Pipette solution

20ml Std. hard water

20 ml hard water sample

20ml boiled hard water sample

Indicator

2 drops of EBT

2 drops of EBT

2 drops of EBT

Additional soln.


Ammoniacal Buffer
solution (5ml)

Ammoniacal Buffer solution
(5ml)

Ammoniacal Buffer solution
(5ml)
End point Wine - red to Steel blue Wine - red to steel blue Wine - red to Steel blue




STANDARDISATION OF EDTA
Titration - I
Std. HARD WATER Vs EDTA Indicator: EBT

S. No.
Volume of std hard
water (ml)
Burette Reading Volume of
EDTA
(V 1) (ml)
Concordant value

Initial

Final



Volume of std .hard water taken = 20 ml
Volume of EDTA consumed (V 1) = --------------- ml
1 ml of std.hard water = 1mg of CaCO 3
20 ml of std hard water = 20 mg of CaCO 3

V 1 ml of EDTA solution containing 20 mg of CaCO 3
1 ml of EDTA solution = 20 / V 1 mg of CaCO 3
= -----------------------mg of CaCO 3


15

Expt. No. 2 DETERMINATION OF TOTAL, TEMPORARY AND
PERMANENT HARDNESS OF WATER

AIM
To estimate the amount of total, temporary & permanent hardness in the given sample of water.

PRINCIPLE
The estimation is based on the complexometric titration.

(i) Total hardness of water is estimated by titrating against EDTA using EBT indicator.
EBT+M ?[EBT-M] (unstable complex)
(EBT-M) (Unstable complex) +EDTA ? [EDTA-M] (stable complex) +EBT
EBT indicator forms wine- red colored complex with metal ions present in water. On addition of EDTA
metal ions preferably forms complexes with EDTA and steel blue EBT indicator is set free. Therefore
change of colour from wine- red to steel blue denotes the end point.

(ii) Temporary hardness is removed by boiling the water.
Ca (HCO 3) 2 ? CaCO 3 +CO 2 ?+H 2O
Mg (HCO 3) 2 ? Mg(OH) 2 +2CO 2 ?
The precipitate is filtered and the remaining permanent hardness is estimated using EDTA.

PROCEDURE

TITRATION ? I
STANDARDISATION OF EDTA

Pipette out 20ml of standard hard water into a 250ml conical flask. Add 5ml of buffer solution and 3
drops of eriochrome black T indictor. Titrate the solution with EDTA from the burette until the colour
changes from wine- red to steel blue at the end point. Repeat the titration for concordant values. Let the
titre value be V 1ml.


16


Titration-II
SAMPLE HARD WATER Vs Std EDTA Indicator: EBT

S.No. Volume of sample
hard water (ml)
Burette Reading Volume of
EDTA
(V 2) (ml)
Concordant value

Initial

Final




CALCULATION

Calculation of total hardness


Volume of EDTA consumed (V 2) = ------------------------- ml
1ml of EDTA = 20 / V 1 mg of CaCO 3
V 2 ml of EDTA = 20 / V 1 x V 2 mg of CaCO 3

( i.e), If 20ml of sample hard water contains 20 x V 2 mg of CaCO 3 / V 1

Then 1000ml of water sample = 20 x V 2 x 1000 / V 1 x 20 mg of CaCO 3

= 1000 x V 2 / V 1 mg of CaCO3

Total hardness of given water sample = ---------------------ppm









17



DETERMINATION OF TOTAL HARDNESS

Pipette out 20ml of sample hard water into a clean conical flask. Add 5ml of buffer solution and 4 -5
drops of Eriochrome black -T indicator. Titrate the wine - red coloured solution with EDTA from the burette until
the colour steel blue appears at the end point. Repeat the titration for concordant values. Let the titre value be
V 2ml.



DETERMINATION OF PERMANENT HARDNESS

Take 100ml of hard water sample in a 500ml beaker and boil gently for about 1hour. Cool, filter it into a
100ml standard flask and make the volume up to the mark. Take 20ml of this solution and proceed it in the same
way as in titration (I). The volume of EDTA consumed corresponds to the permanent hardness of the water
sample. Let the titre value be V 3ml. Temporary hardness is calculated by subtracting permanent hardness from
total hardness.





















18




DETERMINATION OF PERMANENT HARDNESS
BOILED SAMPLE WATER Vs Std. EDTA Indicator: EBT


S.No.
Volume of boiled
hard water (ml)
Burette Reading (ml) Volume of
EDTA
(ml)

Concordant value

Initial Final



CALCULATION OF PERMANENT HARDNESS


Volume of EDTA consumed V 3 = ---------------------ml

1ml of EDTA = 20 / V 1 mg of CaCO 3

V 3ml of EDTA = 20 / V 1 x V 3 mg of CaCO 3

(i.e) 20 ml of boiled sample hard water = 20 / V 1 x V 3 mg of CaCO 3

Then 1000ml of boiled water sample = 20 / V 1 x V 3 / 20 * 1000mg of CaCO 3

= 1000 x V 3 / V 1 mg of CaCO 3

permanent hardness of boiled water sample = -----------------ppm

Temporary hardness of the given water sample = Total hardness ? Permanent hardness

= ------------------ppm

19







RESULT

(i) Total hardness of the given sample water = -------------- ppm.
(ii) Permanent hardness of the given sample water = --------------- ppm.
(iii) Temporary hardness of the given sample water = ----------------ppm.







VIVA-VOCE

1. Define ? Hard water
2. What is the structure of EDTA?
3. How will you calculate temporary hardness?
4. What is the role of the buffer in EDTA titration?
5. What is the permissible limit of hardness in drinking water?
6. Name the hardness producing ions present in water.
7. Name two salts which are responsible for temporary hardness.
8. Why is CaCO 3 taken as the standard?
9. Write the expansion of EDTA.
10. What is meant by EBT?











20





SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II
Standardisation of
AgNO 3
Estimation of Chloride
Burette solution

AgNO 3 solution

Std. AgNO 3 solution

Pipette solution

20ml std KCl solution

20 ml water sample

Indicator

1ml K 2CrO 4

1ml K 2CrO 4


End point

yellow to reddish brown

yellow to reddish brown

Titration I
Std. AgNO3 Vs KCl Indicator: Potassium Chromate













CALCULATION

Volume of KCl (V 1) = ------- ml

Strength of KCl (N 1) = ------- N

Volume of Silver Nitrate (V 2) = -------- ml

Strength of Siver Nitrate V 1N 1
N 2 =
V 1

= --------------------- N

S.No.
Volume of KCl
(ml)
Burette Reading (ml)
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

21




Expt.No. 3 ESTIMATION OF CHLORIDE CONTENT IN WATER
(ARGENTOMETRIC METHOD)
AIM
To estimate the amount of chloride present in given water sample by Argentometric method (Mohr?s
method). You are provided with standard solution of NaCl of strength --------N and a approximately N/10 solution of
Silver nitrate.

PRINCIPLE
The Chloride ion in the form of NaCl, KCl, CaCl 2, MgCl 2 etc., present in the water sample can be estimated
by Argentometric method or known as Mohr?s method. It is an example for precipitation titration. The reaction
between std. Sodium chloride and Silver nitrate is given below.
AgNO 3 + NaCl ? AgCl ? + NaNO 3
The completion of reaction can be observed by employing potassium chromate as the indicator. The end
point is the colour change from yellow to reddish brown due to the following reaction.
2AgNO 3 + K 2CrO 4 ? Ag 2CrO 4 ? + 2KNO 3
Potassium chromate indicator will not be precipitated as silver chromate until all the chlorides in the solution
have been precipitated as AgCl Since a precipitation reaction takes place in preference, this reaction takes place
only at the end point.

PROCEDURE
TITRATION I: STANDARDISATION OF SILVER NITRATE
Pipette out 20ml of standard sodium or potassium chloride solution into a clean conical flask. Add 1ml of 5%
K 2CrO 4 indicator, as the solution turns yellow in colour. Titrate it against silver nitrate solution taken in the burette.
Observe the nearness of the end point through the formation of coagulated silver chloride precipitate at the bottom
of the flask. Now add the silver nitrate drop by drop until the solution gets a faint reddish brown tinge. Repeat the
titration for concordant value. Let the volume of silver nitrate be V 2ml.





22






TITRATION - II

Std AgNO3 Vs WATER SAMPLE Indicator: Potassium Chromate













CALCULATION

Volume of Silver Nitrate (V 3) = ------------ ml

Strength of Siver Nitrate (N 3) = ------------- N

Volume of Water sample (V 4) = -------------- ml

Strength of Water sample V 3 N 3
(N 4) =
V 4

= ----------------- N

Amount of Chloride ion present in 1000 ml of the water sample = Equivalent mass of HCl X 1000


= N 4 x 35.46 x 1000


= -----------------mg/l







S.No.
Volume of water
sample (ml)
Burette Reading
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

23





TITRATION - II
ESTIMATION OF CHLORIDE ION

Pipette out 40 ml of the given water sample into a clean conical flask.To this sample add 1ml of 5% K 2CrO 4
indicator and titrate it against the standardized silver nitrate solution taken in the burette and continue the titration
until the solution produces a reddish brown colour. Note down the end point and repeat the titration for
concordance. Let the volume be V 3ml.







RESULT

The amount of chloride ion present in the water sample = ----------------- mg/l.




VIVA-VOCE

1. Why is this method known as Argentometric method?
2.
What is the chemical reaction between AgNO 3 and Cl
-
ions present in water?

3.
What is the form of Chloride ion present in water?

4. What is the reaction between AgNO 3 and K 2CrO 4 ?
5. What is the name of the method used in this titration?
6. Name the link solution used in the determination.
7. Name the solution used to standardize AgNO 3.
8. What is the indicator used in the determination?
9. How will you calculate the amount of chloride ion in the given solution?
10. What is the colour change in the titration?




24




SHORT PROCEDURE


CONTENTS

TITRATION I

TITRATION II
Burette solution

Std Sodium Hydroxide

Std Sodium Hydroxide

Pipette solution

20 ml hydrochloric acid 20 ml hydrochloric acid
Additional solution


20 ml distilled water

20 ml distilled water


End point



Sudden increase in pH
pH gradual increase

Equivalent Weight of HCl = 36.5







ROUGH GRAPH FAIR GRAPH











pH
? pH/ ? V





Volume of NaOH
(ml)
Volume of NaOH
(ml)





25



Expt. No. 4 DETERMINATION OF STRENGTH OF HCl by pH METRY

AIM
To determine the strength of given HCl by pH metry. A standard solution of 0.1N NaOH is provided.

PRINCIPLE
The pH of a solution is related to H
+
ion concentration by the following formula.

. pH = -log [ H
+
]

pH of a solution is indirectly related to H
+
ion concentration. When NaOH is added slowly to HCl, H
+
ions
get neutralized by OH
-
ions. The pH increases slowly.

H
+
+ Cl
-
+ Na
+
+ OH
-
? Na
+
+ Cl
-
+H 2O

When all H
+
ions of HCl are neutralized at the end point, addition of NaOH causes high increase in pH
because of the addition of excess OH
-
ions.

MATERIALS REQUIRED
pH meter, Glass electrode, Burette, Pipette, Std.NaOH, approximately N/10 HCl .

PROCEDURE

The burette is washed with distilled water, rinsed with the given std. Sodium hydroxide and filled with the
same solution. Exactly 10ml of the given HCl solution is pipetted out into a clean beaker. It is then diluted to 50ml
with distilled water. A glass electrode is dipped into the solution and its terminals are connected to a pH meter.

26

TITRATION - I
S.No Volume of
NaOH (ml)
pH
1

2

3

4

5

6

7

8

9

10


TITRATION - II



CALCULATION

Volume of NaOH (V 1) = ------------------- ml ( titre value)
Strength of NaOH (N 1) = ------------------- N
Volume of HCl (V 2) = ------------------ml
Strength of HCl (N 2) = ------------------ N
N 2 = V 1 N 1 / V 2
Strength of HCl = -------------------- N
Amount of HCl present in 1000ml of the given solution = Strength x equivalent weight of HCl
= ------------------ X 36.5
= --------------------- g
S.No Volume of
NaOH (ml)
pH
11

12

13

14

15

16

17

18

19

20

S.No
Volume of
NaOH (ml)
pH ?pH ?V ?pH / ?V
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
27



Now NaOH is gradually added from the burette to HCl taken in the beaker. pH of the solution is noted for
each addition of NaOH. This process is continued until 5 readings are taken after the end point.
A fair titration is performed to find the exact end point.





RESULT

(i) Strength of the given HCl solution = ---------------- N
(ii) Amount of HCl present in a litre of the solution = ---------------- g


VIVA-VOCE

1. What is meant by pH?
2. What is the name of the reference electrode used ?
3. Why does pH value increase suddenly at the end point?
4. What is the indicator used in the titration?
5. What is the pH range of human blood?
6. What is the unit of pH?
7. How will you calculate the amount of HCl?
8. How is glass electrode represented?
9. Why is glass electrode known as ion selective electrode?
10. What is the chemical reaction involved in this titration?





28




SHORT PROCEDURE


CONTENTS
TITRATION
Burette solution

Std Sodium Hydroxide

Pipette solution

20 ml mixture of acid (HCl+ CH 3COOH)


Additional solution

20 ml distilled water


End point

Conductivity decreases-slowly increases-Sudden increase



Equivalent Weight of HCl = 36.5


Equivalent Weight of CH 3COOH = 60



MODEL GRAPH


Conductance
Volume of NaOH
Mixture of Acids






29




Expt. No. 5 CONDUCTOMETRIC TITRATION OF MIXTURE
OF ACIDS

AIM
To determine the amount of a strong acid and a weak acid present in the given solution.

PRINCIPLE

Solution of electrolytes conducts electricity due to the presence of ions. Since specific conductance of a
solution is proportional to the concentration of ions in it, conductance of the solution is measured during the titration.

HCl + NaOH ? NaCl + H 2O (I neutralization)

CH 3COOH + NaOH ? CH 3COONa + H 2O (II neutralization)

When a solution of HCl is treated with NaOH the fast moving hydrogen ions are progressively replaced by
slow moving sodium ions. As a result conductance of the solution decreases. This decrease will take place until the
first neutralisation point is reached. Further addition of alkali results in formation of sodium acetate.

Since sodium acetate is stronger than acetic acid conductivity slowly increases until all acetic acid is
completely neutralized.(II Neutralisation) This is due to the presence of fast moving OH
-
ions. Anymore addition of
alkali increases the conductance sharply.

PROCEDURE
The burette is filled with NaOH solution upto zero mark. The given unknown solution (mixture of a weak &
a strong acid) is transferred into a 100ml standard flask and made upto the mark with distilled water. 20ml of the
made up solution is pipetted out into a clean 100ml beaker. The solution is diluted to 20ml using distilled water. A
conductivity cell is dipped into the solution and the terminals are connected to a conductivity meter.
30


TITRATION


CALCULATION OF STRENGTH OF HCl
Volume of NaOH (V 1) = --------------- ml (titre value)
Strength of NaOH (N 1) = ---------------- N
Volume of HCl (V 2) = ------------ ml
Strength of HCl (N 2) = -------------- N

N 2 = V 1 N 1 / V 2
Strength of HCl = ---------------- N
CALCULATION OF STRENGTH OF CH3COOH
Volume of NaOH (V 1) = ------------ ml (titre value)
Strength of NaOH (N 1) = ------------ N
Volume of CH 3COOH (V 2) = ------------ ml
Strength of CH 3COOH (N 2) = ------------ N
N 2 = V 1 N 1 / V 2

Strength of CH 3COOH = ------------ N



S.No

Volume of NaOH
(ml)

Conductance (mho)

14

15

16

17
18
19
20

21
22
23
24
25
26

S.No

Volume of NaOH
(ml)

Conductance (mho)

1
2
3
4
5
6
7
8
9
10
11
12
13
31

The burette solution is added to the unknown solution in the beaker in 0.5 ml increments, the solution is
stirred using a glass rod, and the observed conductance values are read from the meter. The conductance values
show decrease in the initial values, then gradually increases and finally shows a steep increase. The titration hence
shows two end-points (i.e) I neutralization (weak acid) & II neutralization (strong acid).
The accurate end-point is obtained by plotting a graph between observed conductance Vs volume of
NaOH added.

RESULT
The strength of acids present in the given unknown solution are:
a) Strong acid = ---------------- N
b) Weak acid = -----------------N



VIVA-VOCE

1. What is weak acid?
2. How many end points are obtained from the graph? Comment two end points.
3. Why is the conductance increase in the first end point?
4. What mixture of acids used in this titration?
5. Write the neutralization reaction between CH 3COOH and NaOH.
6. What is the solution present in the conductivity cell?
7. What are strong and weak electrolytes?
8. Give an example for strong acid and weak acid.
9. What is the strong electrolyte of weak electrolyte?
10. Give an example for strong base.









32

SHORT PROCEDURE



















ROUGH GRAPH







EMF(mV)






Volume of Potassium dichromate (ml)

FAIR GRAPH









? E / ? V

Volume of Potassium dichromate (ml)




CONTENTS

TITRATION I

TITRATION II
Burette solution

Std Potassium dichromate

Std Potassium dichromate

Pipette solution

10 ml of FAS


10 ml of FAS



Additional
solution

20 ml distilled water+
10 ml of dil H 2SO 4


20 ml distilled water+
10 ml of dil H 2SO 4

End point

Sudden increase in EMF

EMF increases and decreases

Equivalent Weight of Ferrous ion = 55.85

33


Expt. No. 6 ESTIMATION OF FERROUS ION BY POTENTIOMETRIC
TITRATION

AIM
To estimate the amount of ferrous ion present in whole of the given solution potentiometrically. A standard
solution of potassium dichromate of strength -----------N is provided.

PRINCIPLE

Potentiometric titrations depend on measurement of emf between reference electrode and an indicator
electrode. When a solution of ferrous iron is titrated with a solution of potassium dichromate, the following redox
reaction takes place.

6Fe
2+
+ Cr 2O 7
2-
+ 14 H
+
? 6Fe
3+
+ 2Cr
3+
+ 7H 2O

During this titration Fe
2+
is converted in to Fe
3+
, whose concentration increases. At the end point, there
will be a sharp change due to sudden removal of all Fe
2+
ions.
The cell is set up by connecting this redox electrode with a calomel electrode as shown below:

Pt, Fe
2+
, Fe
3+
, II KCl , HgCl 2 (s), Hg

A graph between EMF measured against the volume of potassium dichromate added is drawn and the
end point is noted from the graph.

PROCEDURE

10ml of Ferrous solution is pipetted out into a 100 ml beaker. 10ml of dil.H 2SO 4 and 20ml of distilled water
are added. A platinum electrode and a calomel electrode are dipped into this solution and connected to the
potentiometer. Then 1ml of potassium dichromate is added to the solution and stirred well for 30 seconds. The
EMF is measured and the titration is continued by adding potassium dichromate in 1ml increments till five
measurements after the end point.



34


ROUGH TITRATION



S.No.

Volume of dichromate (ml)

EMF (mV)


1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.





35







A graph is drawn by plotting the emf against the volume of potassium dichromate and the end point range is
fixed.


About 20ml of Ferrous solution is pipetted out and the titration is continued by adding 0.1ml increaments of
potassium dichromate in the end point range. The emf is measured for each 0.1ml after stirring the solution well.


A graph is plotted between emf and the volume of potassium dichromate and also a first derivative graph is
plotted ( ? E/ ? V against vol. of K 2Cr 2O 7). The strength of Ferrous solution and the amount of Ferrous ion present are
calculated from the end point.



























36

FAIR TITRATION

S.No Volume of
Dichromate (ml)
Emf (mV) ?E ?V ?E/?V






















CALCULATION

Volume of Potassim dichromate (V 1) = -------------- ml
Normality of Potassium dichromate (N 1) = --------------- N
Volume of Ferrous sulphate (V 2) = --------------- ml
Normality of Ferrous sulphate (N 2) = --------------- N
Amount of Ferrous ion present in 1000ml of the solution = Normality X Equivalent weight of ferrous ion
= --------------- X 55.85 g

The amount of Ferrous ion present in the given solution = ----------------- g






37









RESULT

The amount of Ferrous ion present in the whole of the given solution = --------------- g.








VIVA-VOCE

1. What is EMF?
2. What is the basic principle of potentiometric titration?
3. Why does EMF increase during the titration?
4. Write the cell representation of the titration.
5. What is redox reaction?
6. What is the purpose of adding sulphuric acid?
7. What are the advantages of potentiometric titration?
8. How will you obtain the end point in the titration?
9. What is the name of the indicator electrode used in this titration?
10. What is the name of the reference electrode used?








38



SHORT PROCEDURE



CONTENTS

TITRATION
Burette solution

Sodium Hydroxide

Pipette solution

20 ml HCl


Additional solution

20 ml distilled water


End point

Decrease in conductance- increase in conductance

Equivalent Weight of HCl = 36.5
















Conductance

Volume of NaOH ( ml)









39


Expt.No. 7 CONDUCTOMETRIC TITRATION OF STRONG ACID
WITH STRONG BASE
AIM

To determine the strength of a strong acid by titrating a strong acid and strong base conductometrically. A
standard solution of NaOH of known strength ---------N is provided.

PRINCIPLE
Solution of electrolytes conducts electricity due to the presence of ions. The specific conductance of a
solution is proportional to the concentration of ions in it. The reaction between HCl and NaOH may be represented
as,
HCl +NaOH ? NaCl + H 2O

When a solution of hydrochloric acid is titrated with NaOH, the fast moving hydrogen ions are
progressively replaced by slow moving sodium ions. As a result conductance of the solution decreases, this
decrease in conductance will take place until the end point is reached. Further addition of alkali raises the
conductance sharply, as there is an excess of hydroxide ions.

A graph is drawn between volume of NaOH added and the conductance of solution. The exact end point
is intersection of the two lines.

PROCEDURE

The given HCl is made up in a 100ml standard flask. 10 ml of this solution is pipetted out in a beaker. The
burette is filled with standard sodium hydroxide upto the mark.

A conductivity cell is dipped into the beaker with HCl solution and connected to the terminals of the
conductivity bridge. About 1ml of STD NaOH is added and stirred well for 30 seconds. The conductance is
measured and the titration is continued till five measurements after the endpoint. A graph is plotted for the
conductance values against the volume of NaOH and the endpoint range is fixed.

40


TABLE



CALCULATION
Volume of Sodium Hydroxide (V 1) = ------------- ml
Normality of Sodium Hydroxide (N 1) = ------------- N
Volume of Strong acid (V 2) = ------------- ml
Normality of Strong acid (N 2) = V 1 N 1
V 2

The strength of the given strong acid = ------------- N




S.NO
Volume of NaOH
(ml)
Conductance
(mho)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
41

The above titration is repeated again and the exact endpoint is found out by adding in increments of 0.1ml
of NaOH in the end point range and continued after endpoint upto five readings.
A graph is plotted with the conductance values against the volume of NaOH and then the strength of the
strong acid is found out.


RESULT

The strength of the given strong acid is found to be = --------------- N







VIVA-VOCE

1. What is the basic principle of conductometric titration?
2. Why is conductance decreased and increased during the titration?
3. What is conductance mention its unit?
4. Give some examples for Strong acids and Strong bases.
5. Write the reaction between HCl and NaOH.
6. What is meant by strong base?
7. Explain why HCl is a strong acid?
8. Explain why the strength of burette solution is always greater than the pipette solution in conductometric
titration.
9. What is the equivalent weight of HCl and NaOH?
10. Write the formula that is used to calculate the amount of HCl.











42

ESTIMATION OF COPPER

Alloy solution Vs Std. Na2S2O3 (Thio) Indicator: Starch

S.No.
Volume of
Alloy Solution
(ml)
Burette Reading (ml) Volume of
Thio
(ml)
Concordant value
(ml)
Initial Final

1.

2.

3.












CALCULATION
Volume of Na 2S 2O 3 V 1 = ------------- ml

Strength of Na 2S 2O 3 N 1 = ------------- N

Volume of brass solution V 2 = ------------- ml

Strength of brass solution N 2 = ------------- ?

= V 1 x N I / /V 2

= -------------

Strength of copper solution is = ------------- N



















43


Expt.No.8 ESTIMATION OF COPPER IN BRASS
AIM
To estimate the amount of copper present in the given sample of brass.

PRINCIPLE
Brass is an alloy with 55% copper and 33% zinc and small amount of lead and aluminum. Brass is dissolved
in conc. nitric acid to convert copper present in the alloy to cupric ions. Then copper is estimated iodometrically by
titrating the iodine that was liberated against standard sodium thio sulphate solution using starch as indicator.

2 Cu
2+
+ 4I
-
? 2 CuI + I2
I 2 + 2 Na 2S 2O 3 ? Na 2S 4O 6 + 2NaI

CHEMICALS REQUIRED
0.1N Potassium dichromate, 0.1N sodium thio sulphate, 0.01M EDTA, Con. HNO 3 , , KI, EBT,
NH 3OH / NH 4Cl buffer, Starch.

PROCEDURE
PREPARATION OF BRASS ALLOY SOLUTION

About 0.2g of the sample of brass was weighed accurately and transferred into a clean dry 250ml beaker. To
this about 10ml of con. Nitric acid was added and allowed to boil for a small interval of time till the alloy was dissolved.
This was cooled, diluted with water and made upto 250 ml in a standard flask.

TITRATION I
STANDARDIZATION OF Na2S2O3 WITH K2Cr2O7 SOLUTION
20ml of the standard potassium dichromate solution is pipetted out into a conical flask. 20ml of dil.sulphuric
acid and 10ml of 10% KI are added. The liberated iodine is titrated against sodium thio sulphate taken in the burette till
the colour changes to yellowish green. 1ml of starch is added till the colour changes from blue to light green colour.
Titration is repeated for concordance.
44



CALCULATION


Amount of copper in 1lt of given brass solution = Strength of solution x Eq. Wt of Cu


= ------------------ N x 63.5

= -------------------------

So, Amount of copper in 100ml of given brass solution = ------------------- N x 63.5 x 100 / 1000



ie, ------------g of brass contains = -------------------- g of copper


therefore, % of copper in the given brass sample = ------------------- g x 100


= ------------------ g of brass


= ------------------------ %























45


TITRATION II

ESTIMATION OF COPPER

The brass solution is transferred into the 100ml standard flask and 10ml of dil. sulphuric acid is added and
made up to the mark using distilled water.

20ml of the alloy solutionis pipetted out into a conical flask. To this aqueous ammonia is added in drops till
a blue precipitate of Cu(OH) 2 is formed. One or two drops of acetic acid is added to dissolve the precipitate. To
this 10ml of 10% KI is added and titrated against standard thio sulphate using starch as indicator. The end point is
the disappearance of blue colour and appearance of green colour.



RESULT

The given sample of brass was found to contain copper = ------------- %





VIVA-VOCE



1. What is the composition of brass?
2. What is meant by iodometry?
3. What is the principle used in t his method?
4. What is the role of K 2Cr 2O 7?
5. What is the colour change in this titration?
6. Write the chemical reactions involved in this experiments?
7. How will you find out % of copper in brass?
8. What is the role of indicator?
9. What is the equivalent weight of copper?
10. What is the role of adding aqueous ammonia?


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?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





3


PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)
1. Fundamentals
To provide students with a solid foundation in Mathematics, Science and fundamentals of engineering,
enabling them to apply, to find solutions for engineering problems and use this knowledge to acquire higher
education
2. Core Competence
To train the students in chemistry practicals so that they apply their knowledge and training to compare,
and to analyze various engineering industrial problems to find solutions
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice this enables
them to find solutions for the real time problems in industry, and to design products
4. Professionalism
To inculcate professional and effective communication skills, leadership qualities and team spirit in the
students to make them multi-faceted personalities and develop their ability to relate engineering issues to
broader social context
5. Lifelong Learning/Ethics
To demonstrate and practice ethical and professional responsibilities in the industry and society in the
large, through commitment and lifelong learning needed for successful professional career






4


PROGRAMME OUTCOMES (POs)
To demonstrate and apply knowledge of Mathematics, Science and engineering fundamentals in the following
experiments.
1 .To estimate HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. To determine total, temporary & permanent hardness of water by EDTA method.
3. To determine DO content of water sample by Winkler?s method.
4. To determine chloride content of water sample by Argentometric method.
5. To estimate copper content of the given solution by Iodometry.
6. To determine strength of given hydrochloric acid using pH meter.
7. To determine strength of acids in a mixture of acids using conductivity meter.
8. To determine iron content of the given solution using potentiometer.
9. To estimate iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. To estimate sodium and potassium present in water using flame photometer.
11. To determine molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. To determine Pseudo first order kinetics ? ester hydrolysis.
13. To determine Corrosion experiment ? weight loss method.
14. To estimate CMC.
15. To estimate Phase change in a solid.
16. To determine strength of strong acid vs strong base using conductivity meter.











5

BS8161 - CHEMISTRY LABORATORY
SYLLABUS


? To make the student to acquire practical skills in the determination of water quality
parameters through volumetric and instrumental analysis.

? ???? ??? ???? ?? ???? ? ? ?To acquaint the students with the determination of molecular weight of a polymer by
viscometery.

LIST OF EXPERIMENTS:
1. Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. Determination of total, temporary & permanent hardness of water by EDTA method.
3. Determination of DO content of water sample by Winkler?s method.
4. Determination of chloride content of water sample by Argentometric method.
5. Estimation of copper content of the given solution by Iodometry.
6. Determination of strength of given hydrochloric acid using pH meter.
7. Determination of strength of acids in a mixture of acids using conductivity meter.
8. Estimation of iron content of the given solution using potentiometer.
9. Estimation of iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. Estimation of sodium and potassium present in water using flame photometer.
11. Determination of molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. Pseudo first order kinetics ? ester hydrolysis.
13. Corrosion experiment ? weight loss method.
14. Determination of CMC.
15. Phase change in a solid.
16. Conductometric titration of strong acid vs strong base.




? The students will be outfitted with hands-on knowledge in the quantitative chemical
analysis of water quality related parameters.
COURSE OBJECTIVES
COURSE OUTCOMES
6


INDEX [ SEMESTER ? I ]


S.No.



Date


Experiment

Date of
submission



Mark


Signature

1.

Estimation of HCl using Na 2CO 3 as
primary standard and Determination of
alkalinity in water sample.



2.


Determination of total, temporary &
permanent hardness of water by EDTA
method.



3.


Determination of chloride content of water
sample by argentometric method.



4.


Determination of strength of given
hydrochloric acid using pH meter.



5.


Determination of strength of acids in a
mixture of acids using conductivity meter.



6.


Estimation of iron content of the given
solution using potentiometer.



7.





Conductometric titration of strong acid Vs
strong base.



8.



Estimation of copper content of the given
solution by Iodometry


9.
Estimation of sodium and potassium
present in water using flame photometer




7




CONTENTS


S.No.


NAME OF EXPERIMENT

PAGE
No.
SEMESTER - I
1.
Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in
water sample.
09
2. Determination of total, temporary & permanent hardness of water by EDTA method. 15
3. Determination of chloride content of water sample by Argentometric method. 21
4. Determination of strength of given hydrochloric acid using pH meter. 25
5. Determination of strength of acids in a mixture of acids using conductivity meter. 29
6. Estimation of iron content of the given solution using potentiometer. 33
7. Conductometric titration of strong acid Vs strong base.

39


42

8


Estimation of copper content of the given solution by Iodometry 43
9 Estimation of sodium and potassium present in water using flame photometer 47






8



SHORT PROCEDURE:

CONTENTS
TITRATION
Estimation of alkalinity in water sample
(Std HCl Vs water sample)

Burette solution

Std. HCl


Pipette solution

Water sample


Indicator


(i) Phenolphthalein
(ii) Methyl orange


End point

(i) Disappearance of pink colour
(ii) Appearance of reddish orange colour






Relationship
between P &M
Nature of alkalinity
Amount of individual
alkalinities
OH
-
HCO 3
-


CO 3
2-

P = M

only OH
-

P or M

?
0.0

0.0


2P = M

only CO 3
2-


2P or M


0.0


0.0


?

P =0, M?0

only HCO 3
-



M



0.0



?

0.0


2P > M


OH
-
&CO 3
2-


OH
-
= 2P-M
CO 3
2-
= 2(M-P)


?

0.0

?

P < ? M




HCO 3
-
&CO 3
2-


HCO 3
-
= M-2P
CO 3
2-
= 2P

0.0 ? ?




9





Expt. No. 1 DETERMINATION OF ALKALINITY IN WATER
AIM
To determine the type and amounts of alkalinity in the given water sample. A standard solution of Na 2CO 3
of strength ____N is given.

PRINCIPLE
Alkalinity in water is due to the presence of soluble hydroxides, bicarbonates and carbonates.
Determination of various types and amounts of alkalinity is easily carried out by titration with standard HCl
employing the indicators phenolphthalein and methyl orange independently or in succession.

The following reactions occur when different types of alkalinity are neutralized with acid.

OH
?
+ H
+
? H 2O completed at pH 8.2-9.0 ----- (1)

CO 3
2 ?
+ H
+
? HCO 3
?
----- (2)

HCO 3
?
+ H
+
? (H 2CO 3) ? H 2O + CO 2, completed at pH 4.2-5.5 ----- (3)

Neutralisation (1) & (2) will be notified by phenolphthalein end-point while all the three will be

accounted by
methyl orange end-point. Bicarbonate in eqn. (3) may be due to the existence of soluble free bicarbonate salts and
bicarbonates resulting from half neutralization of soluble carbonates (eqn. (2))

Various steps to be followed

a) A known volume of water sample is titrated against std. HCl using first phenolphthalein indicator till
end-point (P) and the titration is continued without break using methyl orange indicator till the end-
point (M).



10


Titration

Estimation of Alkalinity in water sample

Standard HCl Vs Water sample Indicator: 1. Phenolphthalein
2. Methyl Orange


S.No.
Volume
of water
sample (ml)
Burette Reading
Concordant value

Initial Phenolphthalein End
Point (P)
Methyl Orange End
Point (M)

1

2






CALCULATION

Hydroxide ion alkalinity
Volume of HCl (2P-M) = ???????ml

Strength of HCl = ???????? N

Volume of water sample = ???????...ml

Strength of water sample = Volume of HCl (2P-M) x Strength of HCl
Volume of water sample

=

? Hydroxide ion alkalinity in terms of
CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ??????.mg/l







11




b) From the magnitudes of the P & M, the nature of alkalinity can be arrived as follows:

(i) P = M => Presence of only OH
-

(ii) 2P = M => Presence of only CO 3
2-

(iii) P =0, M=0 => Presence of only HCO 3
-
(iv) 2P > M => Presence of OH
-
& CO 3
2-
(v) 2P < M => Presence of HCO 3
-
& CO 3
2-

(Mixture of OH
-
& HCO3
-
is not listed since they do not exist together and are considered equivalent to CO 3
2-
).

PROCEDURE
TITRATION
ESTIMATION OF ALKALINITY IN WATER SAMPLE

Exactly 20 ml of water sample is pipetted out into a clean conical flask. Few drops of phenolphthalein
indicator are added and titrated against a standardized HCl taken in the burette. The end point is the
disappearance of pink colour, which is noted as P. Few drops of methyl orange indicator is added to the same
solution. The solution turns to yellow. The titration is continued further by adding same HCl without break till the
end point is reached. The end point is the colour change from yellow to reddish orange.

The experiment is repeated to get concordant values. From the magnitudes of P & M values, the type of
alkalinity present in the water sample is inferred and the individual amounts are calculated and reported.










12


Carbonate ion alkalinity

Volume of HCl 2 (M ? P) = ??? ????????ml

Strength of HCl = ??.?????..???...N

Volume of water sample =........................................ml

Strength of water sample = Volume of HCl 2 (M ? P) x Strength of HCl
Volume of water sample

= ???????????.. N




? Carbonate ion alkalinity
in terms of CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ???????????mg/l

















13





RESULT

1) The type of alkalinity present in the water sample = -------------------------ions.

2) The individual amounts of alkalinity present in the water sample:
Hydroxide ion alkalinity

= ----------------- ppm
Carbonate ion alkalinity = ------------------ ppm
Bicarbonate ion alkalinity = ----------------- ppm





VIVA-VOCE


1. What is meant by alkalinity?
2. What are the ions responsible for alkalinity?
3. Why OH
-
and HCO 3
?
ions cannot exist together in water?
4. What are the ions responsible for alkalinity when 2P > M?
5. What is the pH range for both in acidic and basic solutions?
6. What is the colour of phenolphthalein in an acid and in an alkaline solution?
7. What is the purpose of using two indicators in same titration?
8. What are the possible combinations of ions for alkalinity?
9. How is the amount of alkalinity expressed?
10. What are the types of indicator used in this experiment?







14

SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II TITRATION III
Standardisation of
EDTA
(EDTA Vs Std
Hard water)
Determination of
total hardness
(Std EDTA Vs Hard
water sample)
Determination of
permanent hardness
(Std EDTA Vs Boiled
Hard water sample)

Burette solution

EDTA solution

EDTA solution

EDTA solution

Pipette solution

20ml Std. hard water

20 ml hard water sample

20ml boiled hard water sample

Indicator

2 drops of EBT

2 drops of EBT

2 drops of EBT

Additional soln.


Ammoniacal Buffer
solution (5ml)

Ammoniacal Buffer solution
(5ml)

Ammoniacal Buffer solution
(5ml)
End point Wine - red to Steel blue Wine - red to steel blue Wine - red to Steel blue




STANDARDISATION OF EDTA
Titration - I
Std. HARD WATER Vs EDTA Indicator: EBT

S. No.
Volume of std hard
water (ml)
Burette Reading Volume of
EDTA
(V 1) (ml)
Concordant value

Initial

Final



Volume of std .hard water taken = 20 ml
Volume of EDTA consumed (V 1) = --------------- ml
1 ml of std.hard water = 1mg of CaCO 3
20 ml of std hard water = 20 mg of CaCO 3

V 1 ml of EDTA solution containing 20 mg of CaCO 3
1 ml of EDTA solution = 20 / V 1 mg of CaCO 3
= -----------------------mg of CaCO 3


15

Expt. No. 2 DETERMINATION OF TOTAL, TEMPORARY AND
PERMANENT HARDNESS OF WATER

AIM
To estimate the amount of total, temporary & permanent hardness in the given sample of water.

PRINCIPLE
The estimation is based on the complexometric titration.

(i) Total hardness of water is estimated by titrating against EDTA using EBT indicator.
EBT+M ?[EBT-M] (unstable complex)
(EBT-M) (Unstable complex) +EDTA ? [EDTA-M] (stable complex) +EBT
EBT indicator forms wine- red colored complex with metal ions present in water. On addition of EDTA
metal ions preferably forms complexes with EDTA and steel blue EBT indicator is set free. Therefore
change of colour from wine- red to steel blue denotes the end point.

(ii) Temporary hardness is removed by boiling the water.
Ca (HCO 3) 2 ? CaCO 3 +CO 2 ?+H 2O
Mg (HCO 3) 2 ? Mg(OH) 2 +2CO 2 ?
The precipitate is filtered and the remaining permanent hardness is estimated using EDTA.

PROCEDURE

TITRATION ? I
STANDARDISATION OF EDTA

Pipette out 20ml of standard hard water into a 250ml conical flask. Add 5ml of buffer solution and 3
drops of eriochrome black T indictor. Titrate the solution with EDTA from the burette until the colour
changes from wine- red to steel blue at the end point. Repeat the titration for concordant values. Let the
titre value be V 1ml.


16


Titration-II
SAMPLE HARD WATER Vs Std EDTA Indicator: EBT

S.No. Volume of sample
hard water (ml)
Burette Reading Volume of
EDTA
(V 2) (ml)
Concordant value

Initial

Final




CALCULATION

Calculation of total hardness


Volume of EDTA consumed (V 2) = ------------------------- ml
1ml of EDTA = 20 / V 1 mg of CaCO 3
V 2 ml of EDTA = 20 / V 1 x V 2 mg of CaCO 3

( i.e), If 20ml of sample hard water contains 20 x V 2 mg of CaCO 3 / V 1

Then 1000ml of water sample = 20 x V 2 x 1000 / V 1 x 20 mg of CaCO 3

= 1000 x V 2 / V 1 mg of CaCO3

Total hardness of given water sample = ---------------------ppm









17



DETERMINATION OF TOTAL HARDNESS

Pipette out 20ml of sample hard water into a clean conical flask. Add 5ml of buffer solution and 4 -5
drops of Eriochrome black -T indicator. Titrate the wine - red coloured solution with EDTA from the burette until
the colour steel blue appears at the end point. Repeat the titration for concordant values. Let the titre value be
V 2ml.



DETERMINATION OF PERMANENT HARDNESS

Take 100ml of hard water sample in a 500ml beaker and boil gently for about 1hour. Cool, filter it into a
100ml standard flask and make the volume up to the mark. Take 20ml of this solution and proceed it in the same
way as in titration (I). The volume of EDTA consumed corresponds to the permanent hardness of the water
sample. Let the titre value be V 3ml. Temporary hardness is calculated by subtracting permanent hardness from
total hardness.





















18




DETERMINATION OF PERMANENT HARDNESS
BOILED SAMPLE WATER Vs Std. EDTA Indicator: EBT


S.No.
Volume of boiled
hard water (ml)
Burette Reading (ml) Volume of
EDTA
(ml)

Concordant value

Initial Final



CALCULATION OF PERMANENT HARDNESS


Volume of EDTA consumed V 3 = ---------------------ml

1ml of EDTA = 20 / V 1 mg of CaCO 3

V 3ml of EDTA = 20 / V 1 x V 3 mg of CaCO 3

(i.e) 20 ml of boiled sample hard water = 20 / V 1 x V 3 mg of CaCO 3

Then 1000ml of boiled water sample = 20 / V 1 x V 3 / 20 * 1000mg of CaCO 3

= 1000 x V 3 / V 1 mg of CaCO 3

permanent hardness of boiled water sample = -----------------ppm

Temporary hardness of the given water sample = Total hardness ? Permanent hardness

= ------------------ppm

19







RESULT

(i) Total hardness of the given sample water = -------------- ppm.
(ii) Permanent hardness of the given sample water = --------------- ppm.
(iii) Temporary hardness of the given sample water = ----------------ppm.







VIVA-VOCE

1. Define ? Hard water
2. What is the structure of EDTA?
3. How will you calculate temporary hardness?
4. What is the role of the buffer in EDTA titration?
5. What is the permissible limit of hardness in drinking water?
6. Name the hardness producing ions present in water.
7. Name two salts which are responsible for temporary hardness.
8. Why is CaCO 3 taken as the standard?
9. Write the expansion of EDTA.
10. What is meant by EBT?











20





SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II
Standardisation of
AgNO 3
Estimation of Chloride
Burette solution

AgNO 3 solution

Std. AgNO 3 solution

Pipette solution

20ml std KCl solution

20 ml water sample

Indicator

1ml K 2CrO 4

1ml K 2CrO 4


End point

yellow to reddish brown

yellow to reddish brown

Titration I
Std. AgNO3 Vs KCl Indicator: Potassium Chromate













CALCULATION

Volume of KCl (V 1) = ------- ml

Strength of KCl (N 1) = ------- N

Volume of Silver Nitrate (V 2) = -------- ml

Strength of Siver Nitrate V 1N 1
N 2 =
V 1

= --------------------- N

S.No.
Volume of KCl
(ml)
Burette Reading (ml)
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

21




Expt.No. 3 ESTIMATION OF CHLORIDE CONTENT IN WATER
(ARGENTOMETRIC METHOD)
AIM
To estimate the amount of chloride present in given water sample by Argentometric method (Mohr?s
method). You are provided with standard solution of NaCl of strength --------N and a approximately N/10 solution of
Silver nitrate.

PRINCIPLE
The Chloride ion in the form of NaCl, KCl, CaCl 2, MgCl 2 etc., present in the water sample can be estimated
by Argentometric method or known as Mohr?s method. It is an example for precipitation titration. The reaction
between std. Sodium chloride and Silver nitrate is given below.
AgNO 3 + NaCl ? AgCl ? + NaNO 3
The completion of reaction can be observed by employing potassium chromate as the indicator. The end
point is the colour change from yellow to reddish brown due to the following reaction.
2AgNO 3 + K 2CrO 4 ? Ag 2CrO 4 ? + 2KNO 3
Potassium chromate indicator will not be precipitated as silver chromate until all the chlorides in the solution
have been precipitated as AgCl Since a precipitation reaction takes place in preference, this reaction takes place
only at the end point.

PROCEDURE
TITRATION I: STANDARDISATION OF SILVER NITRATE
Pipette out 20ml of standard sodium or potassium chloride solution into a clean conical flask. Add 1ml of 5%
K 2CrO 4 indicator, as the solution turns yellow in colour. Titrate it against silver nitrate solution taken in the burette.
Observe the nearness of the end point through the formation of coagulated silver chloride precipitate at the bottom
of the flask. Now add the silver nitrate drop by drop until the solution gets a faint reddish brown tinge. Repeat the
titration for concordant value. Let the volume of silver nitrate be V 2ml.





22






TITRATION - II

Std AgNO3 Vs WATER SAMPLE Indicator: Potassium Chromate













CALCULATION

Volume of Silver Nitrate (V 3) = ------------ ml

Strength of Siver Nitrate (N 3) = ------------- N

Volume of Water sample (V 4) = -------------- ml

Strength of Water sample V 3 N 3
(N 4) =
V 4

= ----------------- N

Amount of Chloride ion present in 1000 ml of the water sample = Equivalent mass of HCl X 1000


= N 4 x 35.46 x 1000


= -----------------mg/l







S.No.
Volume of water
sample (ml)
Burette Reading
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

23





TITRATION - II
ESTIMATION OF CHLORIDE ION

Pipette out 40 ml of the given water sample into a clean conical flask.To this sample add 1ml of 5% K 2CrO 4
indicator and titrate it against the standardized silver nitrate solution taken in the burette and continue the titration
until the solution produces a reddish brown colour. Note down the end point and repeat the titration for
concordance. Let the volume be V 3ml.







RESULT

The amount of chloride ion present in the water sample = ----------------- mg/l.




VIVA-VOCE

1. Why is this method known as Argentometric method?
2.
What is the chemical reaction between AgNO 3 and Cl
-
ions present in water?

3.
What is the form of Chloride ion present in water?

4. What is the reaction between AgNO 3 and K 2CrO 4 ?
5. What is the name of the method used in this titration?
6. Name the link solution used in the determination.
7. Name the solution used to standardize AgNO 3.
8. What is the indicator used in the determination?
9. How will you calculate the amount of chloride ion in the given solution?
10. What is the colour change in the titration?




24




SHORT PROCEDURE


CONTENTS

TITRATION I

TITRATION II
Burette solution

Std Sodium Hydroxide

Std Sodium Hydroxide

Pipette solution

20 ml hydrochloric acid 20 ml hydrochloric acid
Additional solution


20 ml distilled water

20 ml distilled water


End point



Sudden increase in pH
pH gradual increase

Equivalent Weight of HCl = 36.5







ROUGH GRAPH FAIR GRAPH











pH
? pH/ ? V





Volume of NaOH
(ml)
Volume of NaOH
(ml)





25



Expt. No. 4 DETERMINATION OF STRENGTH OF HCl by pH METRY

AIM
To determine the strength of given HCl by pH metry. A standard solution of 0.1N NaOH is provided.

PRINCIPLE
The pH of a solution is related to H
+
ion concentration by the following formula.

. pH = -log [ H
+
]

pH of a solution is indirectly related to H
+
ion concentration. When NaOH is added slowly to HCl, H
+
ions
get neutralized by OH
-
ions. The pH increases slowly.

H
+
+ Cl
-
+ Na
+
+ OH
-
? Na
+
+ Cl
-
+H 2O

When all H
+
ions of HCl are neutralized at the end point, addition of NaOH causes high increase in pH
because of the addition of excess OH
-
ions.

MATERIALS REQUIRED
pH meter, Glass electrode, Burette, Pipette, Std.NaOH, approximately N/10 HCl .

PROCEDURE

The burette is washed with distilled water, rinsed with the given std. Sodium hydroxide and filled with the
same solution. Exactly 10ml of the given HCl solution is pipetted out into a clean beaker. It is then diluted to 50ml
with distilled water. A glass electrode is dipped into the solution and its terminals are connected to a pH meter.

26

TITRATION - I
S.No Volume of
NaOH (ml)
pH
1

2

3

4

5

6

7

8

9

10


TITRATION - II



CALCULATION

Volume of NaOH (V 1) = ------------------- ml ( titre value)
Strength of NaOH (N 1) = ------------------- N
Volume of HCl (V 2) = ------------------ml
Strength of HCl (N 2) = ------------------ N
N 2 = V 1 N 1 / V 2
Strength of HCl = -------------------- N
Amount of HCl present in 1000ml of the given solution = Strength x equivalent weight of HCl
= ------------------ X 36.5
= --------------------- g
S.No Volume of
NaOH (ml)
pH
11

12

13

14

15

16

17

18

19

20

S.No
Volume of
NaOH (ml)
pH ?pH ?V ?pH / ?V
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
27



Now NaOH is gradually added from the burette to HCl taken in the beaker. pH of the solution is noted for
each addition of NaOH. This process is continued until 5 readings are taken after the end point.
A fair titration is performed to find the exact end point.





RESULT

(i) Strength of the given HCl solution = ---------------- N
(ii) Amount of HCl present in a litre of the solution = ---------------- g


VIVA-VOCE

1. What is meant by pH?
2. What is the name of the reference electrode used ?
3. Why does pH value increase suddenly at the end point?
4. What is the indicator used in the titration?
5. What is the pH range of human blood?
6. What is the unit of pH?
7. How will you calculate the amount of HCl?
8. How is glass electrode represented?
9. Why is glass electrode known as ion selective electrode?
10. What is the chemical reaction involved in this titration?





28




SHORT PROCEDURE


CONTENTS
TITRATION
Burette solution

Std Sodium Hydroxide

Pipette solution

20 ml mixture of acid (HCl+ CH 3COOH)


Additional solution

20 ml distilled water


End point

Conductivity decreases-slowly increases-Sudden increase



Equivalent Weight of HCl = 36.5


Equivalent Weight of CH 3COOH = 60



MODEL GRAPH


Conductance
Volume of NaOH
Mixture of Acids






29




Expt. No. 5 CONDUCTOMETRIC TITRATION OF MIXTURE
OF ACIDS

AIM
To determine the amount of a strong acid and a weak acid present in the given solution.

PRINCIPLE

Solution of electrolytes conducts electricity due to the presence of ions. Since specific conductance of a
solution is proportional to the concentration of ions in it, conductance of the solution is measured during the titration.

HCl + NaOH ? NaCl + H 2O (I neutralization)

CH 3COOH + NaOH ? CH 3COONa + H 2O (II neutralization)

When a solution of HCl is treated with NaOH the fast moving hydrogen ions are progressively replaced by
slow moving sodium ions. As a result conductance of the solution decreases. This decrease will take place until the
first neutralisation point is reached. Further addition of alkali results in formation of sodium acetate.

Since sodium acetate is stronger than acetic acid conductivity slowly increases until all acetic acid is
completely neutralized.(II Neutralisation) This is due to the presence of fast moving OH
-
ions. Anymore addition of
alkali increases the conductance sharply.

PROCEDURE
The burette is filled with NaOH solution upto zero mark. The given unknown solution (mixture of a weak &
a strong acid) is transferred into a 100ml standard flask and made upto the mark with distilled water. 20ml of the
made up solution is pipetted out into a clean 100ml beaker. The solution is diluted to 20ml using distilled water. A
conductivity cell is dipped into the solution and the terminals are connected to a conductivity meter.
30


TITRATION


CALCULATION OF STRENGTH OF HCl
Volume of NaOH (V 1) = --------------- ml (titre value)
Strength of NaOH (N 1) = ---------------- N
Volume of HCl (V 2) = ------------ ml
Strength of HCl (N 2) = -------------- N

N 2 = V 1 N 1 / V 2
Strength of HCl = ---------------- N
CALCULATION OF STRENGTH OF CH3COOH
Volume of NaOH (V 1) = ------------ ml (titre value)
Strength of NaOH (N 1) = ------------ N
Volume of CH 3COOH (V 2) = ------------ ml
Strength of CH 3COOH (N 2) = ------------ N
N 2 = V 1 N 1 / V 2

Strength of CH 3COOH = ------------ N



S.No

Volume of NaOH
(ml)

Conductance (mho)

14

15

16

17
18
19
20

21
22
23
24
25
26

S.No

Volume of NaOH
(ml)

Conductance (mho)

1
2
3
4
5
6
7
8
9
10
11
12
13
31

The burette solution is added to the unknown solution in the beaker in 0.5 ml increments, the solution is
stirred using a glass rod, and the observed conductance values are read from the meter. The conductance values
show decrease in the initial values, then gradually increases and finally shows a steep increase. The titration hence
shows two end-points (i.e) I neutralization (weak acid) & II neutralization (strong acid).
The accurate end-point is obtained by plotting a graph between observed conductance Vs volume of
NaOH added.

RESULT
The strength of acids present in the given unknown solution are:
a) Strong acid = ---------------- N
b) Weak acid = -----------------N



VIVA-VOCE

1. What is weak acid?
2. How many end points are obtained from the graph? Comment two end points.
3. Why is the conductance increase in the first end point?
4. What mixture of acids used in this titration?
5. Write the neutralization reaction between CH 3COOH and NaOH.
6. What is the solution present in the conductivity cell?
7. What are strong and weak electrolytes?
8. Give an example for strong acid and weak acid.
9. What is the strong electrolyte of weak electrolyte?
10. Give an example for strong base.









32

SHORT PROCEDURE



















ROUGH GRAPH







EMF(mV)






Volume of Potassium dichromate (ml)

FAIR GRAPH









? E / ? V

Volume of Potassium dichromate (ml)




CONTENTS

TITRATION I

TITRATION II
Burette solution

Std Potassium dichromate

Std Potassium dichromate

Pipette solution

10 ml of FAS


10 ml of FAS



Additional
solution

20 ml distilled water+
10 ml of dil H 2SO 4


20 ml distilled water+
10 ml of dil H 2SO 4

End point

Sudden increase in EMF

EMF increases and decreases

Equivalent Weight of Ferrous ion = 55.85

33


Expt. No. 6 ESTIMATION OF FERROUS ION BY POTENTIOMETRIC
TITRATION

AIM
To estimate the amount of ferrous ion present in whole of the given solution potentiometrically. A standard
solution of potassium dichromate of strength -----------N is provided.

PRINCIPLE

Potentiometric titrations depend on measurement of emf between reference electrode and an indicator
electrode. When a solution of ferrous iron is titrated with a solution of potassium dichromate, the following redox
reaction takes place.

6Fe
2+
+ Cr 2O 7
2-
+ 14 H
+
? 6Fe
3+
+ 2Cr
3+
+ 7H 2O

During this titration Fe
2+
is converted in to Fe
3+
, whose concentration increases. At the end point, there
will be a sharp change due to sudden removal of all Fe
2+
ions.
The cell is set up by connecting this redox electrode with a calomel electrode as shown below:

Pt, Fe
2+
, Fe
3+
, II KCl , HgCl 2 (s), Hg

A graph between EMF measured against the volume of potassium dichromate added is drawn and the
end point is noted from the graph.

PROCEDURE

10ml of Ferrous solution is pipetted out into a 100 ml beaker. 10ml of dil.H 2SO 4 and 20ml of distilled water
are added. A platinum electrode and a calomel electrode are dipped into this solution and connected to the
potentiometer. Then 1ml of potassium dichromate is added to the solution and stirred well for 30 seconds. The
EMF is measured and the titration is continued by adding potassium dichromate in 1ml increments till five
measurements after the end point.



34


ROUGH TITRATION



S.No.

Volume of dichromate (ml)

EMF (mV)


1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.





35







A graph is drawn by plotting the emf against the volume of potassium dichromate and the end point range is
fixed.


About 20ml of Ferrous solution is pipetted out and the titration is continued by adding 0.1ml increaments of
potassium dichromate in the end point range. The emf is measured for each 0.1ml after stirring the solution well.


A graph is plotted between emf and the volume of potassium dichromate and also a first derivative graph is
plotted ( ? E/ ? V against vol. of K 2Cr 2O 7). The strength of Ferrous solution and the amount of Ferrous ion present are
calculated from the end point.



























36

FAIR TITRATION

S.No Volume of
Dichromate (ml)
Emf (mV) ?E ?V ?E/?V






















CALCULATION

Volume of Potassim dichromate (V 1) = -------------- ml
Normality of Potassium dichromate (N 1) = --------------- N
Volume of Ferrous sulphate (V 2) = --------------- ml
Normality of Ferrous sulphate (N 2) = --------------- N
Amount of Ferrous ion present in 1000ml of the solution = Normality X Equivalent weight of ferrous ion
= --------------- X 55.85 g

The amount of Ferrous ion present in the given solution = ----------------- g






37









RESULT

The amount of Ferrous ion present in the whole of the given solution = --------------- g.








VIVA-VOCE

1. What is EMF?
2. What is the basic principle of potentiometric titration?
3. Why does EMF increase during the titration?
4. Write the cell representation of the titration.
5. What is redox reaction?
6. What is the purpose of adding sulphuric acid?
7. What are the advantages of potentiometric titration?
8. How will you obtain the end point in the titration?
9. What is the name of the indicator electrode used in this titration?
10. What is the name of the reference electrode used?








38



SHORT PROCEDURE



CONTENTS

TITRATION
Burette solution

Sodium Hydroxide

Pipette solution

20 ml HCl


Additional solution

20 ml distilled water


End point

Decrease in conductance- increase in conductance

Equivalent Weight of HCl = 36.5
















Conductance

Volume of NaOH ( ml)









39


Expt.No. 7 CONDUCTOMETRIC TITRATION OF STRONG ACID
WITH STRONG BASE
AIM

To determine the strength of a strong acid by titrating a strong acid and strong base conductometrically. A
standard solution of NaOH of known strength ---------N is provided.

PRINCIPLE
Solution of electrolytes conducts electricity due to the presence of ions. The specific conductance of a
solution is proportional to the concentration of ions in it. The reaction between HCl and NaOH may be represented
as,
HCl +NaOH ? NaCl + H 2O

When a solution of hydrochloric acid is titrated with NaOH, the fast moving hydrogen ions are
progressively replaced by slow moving sodium ions. As a result conductance of the solution decreases, this
decrease in conductance will take place until the end point is reached. Further addition of alkali raises the
conductance sharply, as there is an excess of hydroxide ions.

A graph is drawn between volume of NaOH added and the conductance of solution. The exact end point
is intersection of the two lines.

PROCEDURE

The given HCl is made up in a 100ml standard flask. 10 ml of this solution is pipetted out in a beaker. The
burette is filled with standard sodium hydroxide upto the mark.

A conductivity cell is dipped into the beaker with HCl solution and connected to the terminals of the
conductivity bridge. About 1ml of STD NaOH is added and stirred well for 30 seconds. The conductance is
measured and the titration is continued till five measurements after the endpoint. A graph is plotted for the
conductance values against the volume of NaOH and the endpoint range is fixed.

40


TABLE



CALCULATION
Volume of Sodium Hydroxide (V 1) = ------------- ml
Normality of Sodium Hydroxide (N 1) = ------------- N
Volume of Strong acid (V 2) = ------------- ml
Normality of Strong acid (N 2) = V 1 N 1
V 2

The strength of the given strong acid = ------------- N




S.NO
Volume of NaOH
(ml)
Conductance
(mho)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
41

The above titration is repeated again and the exact endpoint is found out by adding in increments of 0.1ml
of NaOH in the end point range and continued after endpoint upto five readings.
A graph is plotted with the conductance values against the volume of NaOH and then the strength of the
strong acid is found out.


RESULT

The strength of the given strong acid is found to be = --------------- N







VIVA-VOCE

1. What is the basic principle of conductometric titration?
2. Why is conductance decreased and increased during the titration?
3. What is conductance mention its unit?
4. Give some examples for Strong acids and Strong bases.
5. Write the reaction between HCl and NaOH.
6. What is meant by strong base?
7. Explain why HCl is a strong acid?
8. Explain why the strength of burette solution is always greater than the pipette solution in conductometric
titration.
9. What is the equivalent weight of HCl and NaOH?
10. Write the formula that is used to calculate the amount of HCl.











42

ESTIMATION OF COPPER

Alloy solution Vs Std. Na2S2O3 (Thio) Indicator: Starch

S.No.
Volume of
Alloy Solution
(ml)
Burette Reading (ml) Volume of
Thio
(ml)
Concordant value
(ml)
Initial Final

1.

2.

3.












CALCULATION
Volume of Na 2S 2O 3 V 1 = ------------- ml

Strength of Na 2S 2O 3 N 1 = ------------- N

Volume of brass solution V 2 = ------------- ml

Strength of brass solution N 2 = ------------- ?

= V 1 x N I / /V 2

= -------------

Strength of copper solution is = ------------- N



















43


Expt.No.8 ESTIMATION OF COPPER IN BRASS
AIM
To estimate the amount of copper present in the given sample of brass.

PRINCIPLE
Brass is an alloy with 55% copper and 33% zinc and small amount of lead and aluminum. Brass is dissolved
in conc. nitric acid to convert copper present in the alloy to cupric ions. Then copper is estimated iodometrically by
titrating the iodine that was liberated against standard sodium thio sulphate solution using starch as indicator.

2 Cu
2+
+ 4I
-
? 2 CuI + I2
I 2 + 2 Na 2S 2O 3 ? Na 2S 4O 6 + 2NaI

CHEMICALS REQUIRED
0.1N Potassium dichromate, 0.1N sodium thio sulphate, 0.01M EDTA, Con. HNO 3 , , KI, EBT,
NH 3OH / NH 4Cl buffer, Starch.

PROCEDURE
PREPARATION OF BRASS ALLOY SOLUTION

About 0.2g of the sample of brass was weighed accurately and transferred into a clean dry 250ml beaker. To
this about 10ml of con. Nitric acid was added and allowed to boil for a small interval of time till the alloy was dissolved.
This was cooled, diluted with water and made upto 250 ml in a standard flask.

TITRATION I
STANDARDIZATION OF Na2S2O3 WITH K2Cr2O7 SOLUTION
20ml of the standard potassium dichromate solution is pipetted out into a conical flask. 20ml of dil.sulphuric
acid and 10ml of 10% KI are added. The liberated iodine is titrated against sodium thio sulphate taken in the burette till
the colour changes to yellowish green. 1ml of starch is added till the colour changes from blue to light green colour.
Titration is repeated for concordance.
44



CALCULATION


Amount of copper in 1lt of given brass solution = Strength of solution x Eq. Wt of Cu


= ------------------ N x 63.5

= -------------------------

So, Amount of copper in 100ml of given brass solution = ------------------- N x 63.5 x 100 / 1000



ie, ------------g of brass contains = -------------------- g of copper


therefore, % of copper in the given brass sample = ------------------- g x 100


= ------------------ g of brass


= ------------------------ %























45


TITRATION II

ESTIMATION OF COPPER

The brass solution is transferred into the 100ml standard flask and 10ml of dil. sulphuric acid is added and
made up to the mark using distilled water.

20ml of the alloy solutionis pipetted out into a conical flask. To this aqueous ammonia is added in drops till
a blue precipitate of Cu(OH) 2 is formed. One or two drops of acetic acid is added to dissolve the precipitate. To
this 10ml of 10% KI is added and titrated against standard thio sulphate using starch as indicator. The end point is
the disappearance of blue colour and appearance of green colour.



RESULT

The given sample of brass was found to contain copper = ------------- %





VIVA-VOCE



1. What is the composition of brass?
2. What is meant by iodometry?
3. What is the principle used in t his method?
4. What is the role of K 2Cr 2O 7?
5. What is the colour change in this titration?
6. Write the chemical reactions involved in this experiments?
7. How will you find out % of copper in brass?
8. What is the role of indicator?
9. What is the equivalent weight of copper?
10. What is the role of adding aqueous ammonia?


46


SHORT PROCEDURE
Standard solutions are prepared by the dilution of the given stock solution. The flasks are numbered and
the solutions are prepared according to the following table using different glass pipettes.



Flask number

1 2 3 4 5 6
Vol. of pipette to use 1 1 2 10 10 10
Vol. of Na stock solution to pipette 0.5 1 2 4 6 8
Conc. of solution obtained (?g/ml) 5 10 10 40 60 80



MODEL GRAPH








ABSORBANCE






CONCENTRATION








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?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





3


PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)
1. Fundamentals
To provide students with a solid foundation in Mathematics, Science and fundamentals of engineering,
enabling them to apply, to find solutions for engineering problems and use this knowledge to acquire higher
education
2. Core Competence
To train the students in chemistry practicals so that they apply their knowledge and training to compare,
and to analyze various engineering industrial problems to find solutions
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice this enables
them to find solutions for the real time problems in industry, and to design products
4. Professionalism
To inculcate professional and effective communication skills, leadership qualities and team spirit in the
students to make them multi-faceted personalities and develop their ability to relate engineering issues to
broader social context
5. Lifelong Learning/Ethics
To demonstrate and practice ethical and professional responsibilities in the industry and society in the
large, through commitment and lifelong learning needed for successful professional career






4


PROGRAMME OUTCOMES (POs)
To demonstrate and apply knowledge of Mathematics, Science and engineering fundamentals in the following
experiments.
1 .To estimate HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. To determine total, temporary & permanent hardness of water by EDTA method.
3. To determine DO content of water sample by Winkler?s method.
4. To determine chloride content of water sample by Argentometric method.
5. To estimate copper content of the given solution by Iodometry.
6. To determine strength of given hydrochloric acid using pH meter.
7. To determine strength of acids in a mixture of acids using conductivity meter.
8. To determine iron content of the given solution using potentiometer.
9. To estimate iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. To estimate sodium and potassium present in water using flame photometer.
11. To determine molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. To determine Pseudo first order kinetics ? ester hydrolysis.
13. To determine Corrosion experiment ? weight loss method.
14. To estimate CMC.
15. To estimate Phase change in a solid.
16. To determine strength of strong acid vs strong base using conductivity meter.











5

BS8161 - CHEMISTRY LABORATORY
SYLLABUS


? To make the student to acquire practical skills in the determination of water quality
parameters through volumetric and instrumental analysis.

? ???? ??? ???? ?? ???? ? ? ?To acquaint the students with the determination of molecular weight of a polymer by
viscometery.

LIST OF EXPERIMENTS:
1. Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. Determination of total, temporary & permanent hardness of water by EDTA method.
3. Determination of DO content of water sample by Winkler?s method.
4. Determination of chloride content of water sample by Argentometric method.
5. Estimation of copper content of the given solution by Iodometry.
6. Determination of strength of given hydrochloric acid using pH meter.
7. Determination of strength of acids in a mixture of acids using conductivity meter.
8. Estimation of iron content of the given solution using potentiometer.
9. Estimation of iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. Estimation of sodium and potassium present in water using flame photometer.
11. Determination of molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. Pseudo first order kinetics ? ester hydrolysis.
13. Corrosion experiment ? weight loss method.
14. Determination of CMC.
15. Phase change in a solid.
16. Conductometric titration of strong acid vs strong base.




? The students will be outfitted with hands-on knowledge in the quantitative chemical
analysis of water quality related parameters.
COURSE OBJECTIVES
COURSE OUTCOMES
6


INDEX [ SEMESTER ? I ]


S.No.



Date


Experiment

Date of
submission



Mark


Signature

1.

Estimation of HCl using Na 2CO 3 as
primary standard and Determination of
alkalinity in water sample.



2.


Determination of total, temporary &
permanent hardness of water by EDTA
method.



3.


Determination of chloride content of water
sample by argentometric method.



4.


Determination of strength of given
hydrochloric acid using pH meter.



5.


Determination of strength of acids in a
mixture of acids using conductivity meter.



6.


Estimation of iron content of the given
solution using potentiometer.



7.





Conductometric titration of strong acid Vs
strong base.



8.



Estimation of copper content of the given
solution by Iodometry


9.
Estimation of sodium and potassium
present in water using flame photometer




7




CONTENTS


S.No.


NAME OF EXPERIMENT

PAGE
No.
SEMESTER - I
1.
Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in
water sample.
09
2. Determination of total, temporary & permanent hardness of water by EDTA method. 15
3. Determination of chloride content of water sample by Argentometric method. 21
4. Determination of strength of given hydrochloric acid using pH meter. 25
5. Determination of strength of acids in a mixture of acids using conductivity meter. 29
6. Estimation of iron content of the given solution using potentiometer. 33
7. Conductometric titration of strong acid Vs strong base.

39


42

8


Estimation of copper content of the given solution by Iodometry 43
9 Estimation of sodium and potassium present in water using flame photometer 47






8



SHORT PROCEDURE:

CONTENTS
TITRATION
Estimation of alkalinity in water sample
(Std HCl Vs water sample)

Burette solution

Std. HCl


Pipette solution

Water sample


Indicator


(i) Phenolphthalein
(ii) Methyl orange


End point

(i) Disappearance of pink colour
(ii) Appearance of reddish orange colour






Relationship
between P &M
Nature of alkalinity
Amount of individual
alkalinities
OH
-
HCO 3
-


CO 3
2-

P = M

only OH
-

P or M

?
0.0

0.0


2P = M

only CO 3
2-


2P or M


0.0


0.0


?

P =0, M?0

only HCO 3
-



M



0.0



?

0.0


2P > M


OH
-
&CO 3
2-


OH
-
= 2P-M
CO 3
2-
= 2(M-P)


?

0.0

?

P < ? M




HCO 3
-
&CO 3
2-


HCO 3
-
= M-2P
CO 3
2-
= 2P

0.0 ? ?




9





Expt. No. 1 DETERMINATION OF ALKALINITY IN WATER
AIM
To determine the type and amounts of alkalinity in the given water sample. A standard solution of Na 2CO 3
of strength ____N is given.

PRINCIPLE
Alkalinity in water is due to the presence of soluble hydroxides, bicarbonates and carbonates.
Determination of various types and amounts of alkalinity is easily carried out by titration with standard HCl
employing the indicators phenolphthalein and methyl orange independently or in succession.

The following reactions occur when different types of alkalinity are neutralized with acid.

OH
?
+ H
+
? H 2O completed at pH 8.2-9.0 ----- (1)

CO 3
2 ?
+ H
+
? HCO 3
?
----- (2)

HCO 3
?
+ H
+
? (H 2CO 3) ? H 2O + CO 2, completed at pH 4.2-5.5 ----- (3)

Neutralisation (1) & (2) will be notified by phenolphthalein end-point while all the three will be

accounted by
methyl orange end-point. Bicarbonate in eqn. (3) may be due to the existence of soluble free bicarbonate salts and
bicarbonates resulting from half neutralization of soluble carbonates (eqn. (2))

Various steps to be followed

a) A known volume of water sample is titrated against std. HCl using first phenolphthalein indicator till
end-point (P) and the titration is continued without break using methyl orange indicator till the end-
point (M).



10


Titration

Estimation of Alkalinity in water sample

Standard HCl Vs Water sample Indicator: 1. Phenolphthalein
2. Methyl Orange


S.No.
Volume
of water
sample (ml)
Burette Reading
Concordant value

Initial Phenolphthalein End
Point (P)
Methyl Orange End
Point (M)

1

2






CALCULATION

Hydroxide ion alkalinity
Volume of HCl (2P-M) = ???????ml

Strength of HCl = ???????? N

Volume of water sample = ???????...ml

Strength of water sample = Volume of HCl (2P-M) x Strength of HCl
Volume of water sample

=

? Hydroxide ion alkalinity in terms of
CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ??????.mg/l







11




b) From the magnitudes of the P & M, the nature of alkalinity can be arrived as follows:

(i) P = M => Presence of only OH
-

(ii) 2P = M => Presence of only CO 3
2-

(iii) P =0, M=0 => Presence of only HCO 3
-
(iv) 2P > M => Presence of OH
-
& CO 3
2-
(v) 2P < M => Presence of HCO 3
-
& CO 3
2-

(Mixture of OH
-
& HCO3
-
is not listed since they do not exist together and are considered equivalent to CO 3
2-
).

PROCEDURE
TITRATION
ESTIMATION OF ALKALINITY IN WATER SAMPLE

Exactly 20 ml of water sample is pipetted out into a clean conical flask. Few drops of phenolphthalein
indicator are added and titrated against a standardized HCl taken in the burette. The end point is the
disappearance of pink colour, which is noted as P. Few drops of methyl orange indicator is added to the same
solution. The solution turns to yellow. The titration is continued further by adding same HCl without break till the
end point is reached. The end point is the colour change from yellow to reddish orange.

The experiment is repeated to get concordant values. From the magnitudes of P & M values, the type of
alkalinity present in the water sample is inferred and the individual amounts are calculated and reported.










12


Carbonate ion alkalinity

Volume of HCl 2 (M ? P) = ??? ????????ml

Strength of HCl = ??.?????..???...N

Volume of water sample =........................................ml

Strength of water sample = Volume of HCl 2 (M ? P) x Strength of HCl
Volume of water sample

= ???????????.. N




? Carbonate ion alkalinity
in terms of CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ???????????mg/l

















13





RESULT

1) The type of alkalinity present in the water sample = -------------------------ions.

2) The individual amounts of alkalinity present in the water sample:
Hydroxide ion alkalinity

= ----------------- ppm
Carbonate ion alkalinity = ------------------ ppm
Bicarbonate ion alkalinity = ----------------- ppm





VIVA-VOCE


1. What is meant by alkalinity?
2. What are the ions responsible for alkalinity?
3. Why OH
-
and HCO 3
?
ions cannot exist together in water?
4. What are the ions responsible for alkalinity when 2P > M?
5. What is the pH range for both in acidic and basic solutions?
6. What is the colour of phenolphthalein in an acid and in an alkaline solution?
7. What is the purpose of using two indicators in same titration?
8. What are the possible combinations of ions for alkalinity?
9. How is the amount of alkalinity expressed?
10. What are the types of indicator used in this experiment?







14

SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II TITRATION III
Standardisation of
EDTA
(EDTA Vs Std
Hard water)
Determination of
total hardness
(Std EDTA Vs Hard
water sample)
Determination of
permanent hardness
(Std EDTA Vs Boiled
Hard water sample)

Burette solution

EDTA solution

EDTA solution

EDTA solution

Pipette solution

20ml Std. hard water

20 ml hard water sample

20ml boiled hard water sample

Indicator

2 drops of EBT

2 drops of EBT

2 drops of EBT

Additional soln.


Ammoniacal Buffer
solution (5ml)

Ammoniacal Buffer solution
(5ml)

Ammoniacal Buffer solution
(5ml)
End point Wine - red to Steel blue Wine - red to steel blue Wine - red to Steel blue




STANDARDISATION OF EDTA
Titration - I
Std. HARD WATER Vs EDTA Indicator: EBT

S. No.
Volume of std hard
water (ml)
Burette Reading Volume of
EDTA
(V 1) (ml)
Concordant value

Initial

Final



Volume of std .hard water taken = 20 ml
Volume of EDTA consumed (V 1) = --------------- ml
1 ml of std.hard water = 1mg of CaCO 3
20 ml of std hard water = 20 mg of CaCO 3

V 1 ml of EDTA solution containing 20 mg of CaCO 3
1 ml of EDTA solution = 20 / V 1 mg of CaCO 3
= -----------------------mg of CaCO 3


15

Expt. No. 2 DETERMINATION OF TOTAL, TEMPORARY AND
PERMANENT HARDNESS OF WATER

AIM
To estimate the amount of total, temporary & permanent hardness in the given sample of water.

PRINCIPLE
The estimation is based on the complexometric titration.

(i) Total hardness of water is estimated by titrating against EDTA using EBT indicator.
EBT+M ?[EBT-M] (unstable complex)
(EBT-M) (Unstable complex) +EDTA ? [EDTA-M] (stable complex) +EBT
EBT indicator forms wine- red colored complex with metal ions present in water. On addition of EDTA
metal ions preferably forms complexes with EDTA and steel blue EBT indicator is set free. Therefore
change of colour from wine- red to steel blue denotes the end point.

(ii) Temporary hardness is removed by boiling the water.
Ca (HCO 3) 2 ? CaCO 3 +CO 2 ?+H 2O
Mg (HCO 3) 2 ? Mg(OH) 2 +2CO 2 ?
The precipitate is filtered and the remaining permanent hardness is estimated using EDTA.

PROCEDURE

TITRATION ? I
STANDARDISATION OF EDTA

Pipette out 20ml of standard hard water into a 250ml conical flask. Add 5ml of buffer solution and 3
drops of eriochrome black T indictor. Titrate the solution with EDTA from the burette until the colour
changes from wine- red to steel blue at the end point. Repeat the titration for concordant values. Let the
titre value be V 1ml.


16


Titration-II
SAMPLE HARD WATER Vs Std EDTA Indicator: EBT

S.No. Volume of sample
hard water (ml)
Burette Reading Volume of
EDTA
(V 2) (ml)
Concordant value

Initial

Final




CALCULATION

Calculation of total hardness


Volume of EDTA consumed (V 2) = ------------------------- ml
1ml of EDTA = 20 / V 1 mg of CaCO 3
V 2 ml of EDTA = 20 / V 1 x V 2 mg of CaCO 3

( i.e), If 20ml of sample hard water contains 20 x V 2 mg of CaCO 3 / V 1

Then 1000ml of water sample = 20 x V 2 x 1000 / V 1 x 20 mg of CaCO 3

= 1000 x V 2 / V 1 mg of CaCO3

Total hardness of given water sample = ---------------------ppm









17



DETERMINATION OF TOTAL HARDNESS

Pipette out 20ml of sample hard water into a clean conical flask. Add 5ml of buffer solution and 4 -5
drops of Eriochrome black -T indicator. Titrate the wine - red coloured solution with EDTA from the burette until
the colour steel blue appears at the end point. Repeat the titration for concordant values. Let the titre value be
V 2ml.



DETERMINATION OF PERMANENT HARDNESS

Take 100ml of hard water sample in a 500ml beaker and boil gently for about 1hour. Cool, filter it into a
100ml standard flask and make the volume up to the mark. Take 20ml of this solution and proceed it in the same
way as in titration (I). The volume of EDTA consumed corresponds to the permanent hardness of the water
sample. Let the titre value be V 3ml. Temporary hardness is calculated by subtracting permanent hardness from
total hardness.





















18




DETERMINATION OF PERMANENT HARDNESS
BOILED SAMPLE WATER Vs Std. EDTA Indicator: EBT


S.No.
Volume of boiled
hard water (ml)
Burette Reading (ml) Volume of
EDTA
(ml)

Concordant value

Initial Final



CALCULATION OF PERMANENT HARDNESS


Volume of EDTA consumed V 3 = ---------------------ml

1ml of EDTA = 20 / V 1 mg of CaCO 3

V 3ml of EDTA = 20 / V 1 x V 3 mg of CaCO 3

(i.e) 20 ml of boiled sample hard water = 20 / V 1 x V 3 mg of CaCO 3

Then 1000ml of boiled water sample = 20 / V 1 x V 3 / 20 * 1000mg of CaCO 3

= 1000 x V 3 / V 1 mg of CaCO 3

permanent hardness of boiled water sample = -----------------ppm

Temporary hardness of the given water sample = Total hardness ? Permanent hardness

= ------------------ppm

19







RESULT

(i) Total hardness of the given sample water = -------------- ppm.
(ii) Permanent hardness of the given sample water = --------------- ppm.
(iii) Temporary hardness of the given sample water = ----------------ppm.







VIVA-VOCE

1. Define ? Hard water
2. What is the structure of EDTA?
3. How will you calculate temporary hardness?
4. What is the role of the buffer in EDTA titration?
5. What is the permissible limit of hardness in drinking water?
6. Name the hardness producing ions present in water.
7. Name two salts which are responsible for temporary hardness.
8. Why is CaCO 3 taken as the standard?
9. Write the expansion of EDTA.
10. What is meant by EBT?











20





SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II
Standardisation of
AgNO 3
Estimation of Chloride
Burette solution

AgNO 3 solution

Std. AgNO 3 solution

Pipette solution

20ml std KCl solution

20 ml water sample

Indicator

1ml K 2CrO 4

1ml K 2CrO 4


End point

yellow to reddish brown

yellow to reddish brown

Titration I
Std. AgNO3 Vs KCl Indicator: Potassium Chromate













CALCULATION

Volume of KCl (V 1) = ------- ml

Strength of KCl (N 1) = ------- N

Volume of Silver Nitrate (V 2) = -------- ml

Strength of Siver Nitrate V 1N 1
N 2 =
V 1

= --------------------- N

S.No.
Volume of KCl
(ml)
Burette Reading (ml)
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

21




Expt.No. 3 ESTIMATION OF CHLORIDE CONTENT IN WATER
(ARGENTOMETRIC METHOD)
AIM
To estimate the amount of chloride present in given water sample by Argentometric method (Mohr?s
method). You are provided with standard solution of NaCl of strength --------N and a approximately N/10 solution of
Silver nitrate.

PRINCIPLE
The Chloride ion in the form of NaCl, KCl, CaCl 2, MgCl 2 etc., present in the water sample can be estimated
by Argentometric method or known as Mohr?s method. It is an example for precipitation titration. The reaction
between std. Sodium chloride and Silver nitrate is given below.
AgNO 3 + NaCl ? AgCl ? + NaNO 3
The completion of reaction can be observed by employing potassium chromate as the indicator. The end
point is the colour change from yellow to reddish brown due to the following reaction.
2AgNO 3 + K 2CrO 4 ? Ag 2CrO 4 ? + 2KNO 3
Potassium chromate indicator will not be precipitated as silver chromate until all the chlorides in the solution
have been precipitated as AgCl Since a precipitation reaction takes place in preference, this reaction takes place
only at the end point.

PROCEDURE
TITRATION I: STANDARDISATION OF SILVER NITRATE
Pipette out 20ml of standard sodium or potassium chloride solution into a clean conical flask. Add 1ml of 5%
K 2CrO 4 indicator, as the solution turns yellow in colour. Titrate it against silver nitrate solution taken in the burette.
Observe the nearness of the end point through the formation of coagulated silver chloride precipitate at the bottom
of the flask. Now add the silver nitrate drop by drop until the solution gets a faint reddish brown tinge. Repeat the
titration for concordant value. Let the volume of silver nitrate be V 2ml.





22






TITRATION - II

Std AgNO3 Vs WATER SAMPLE Indicator: Potassium Chromate













CALCULATION

Volume of Silver Nitrate (V 3) = ------------ ml

Strength of Siver Nitrate (N 3) = ------------- N

Volume of Water sample (V 4) = -------------- ml

Strength of Water sample V 3 N 3
(N 4) =
V 4

= ----------------- N

Amount of Chloride ion present in 1000 ml of the water sample = Equivalent mass of HCl X 1000


= N 4 x 35.46 x 1000


= -----------------mg/l







S.No.
Volume of water
sample (ml)
Burette Reading
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

23





TITRATION - II
ESTIMATION OF CHLORIDE ION

Pipette out 40 ml of the given water sample into a clean conical flask.To this sample add 1ml of 5% K 2CrO 4
indicator and titrate it against the standardized silver nitrate solution taken in the burette and continue the titration
until the solution produces a reddish brown colour. Note down the end point and repeat the titration for
concordance. Let the volume be V 3ml.







RESULT

The amount of chloride ion present in the water sample = ----------------- mg/l.




VIVA-VOCE

1. Why is this method known as Argentometric method?
2.
What is the chemical reaction between AgNO 3 and Cl
-
ions present in water?

3.
What is the form of Chloride ion present in water?

4. What is the reaction between AgNO 3 and K 2CrO 4 ?
5. What is the name of the method used in this titration?
6. Name the link solution used in the determination.
7. Name the solution used to standardize AgNO 3.
8. What is the indicator used in the determination?
9. How will you calculate the amount of chloride ion in the given solution?
10. What is the colour change in the titration?




24




SHORT PROCEDURE


CONTENTS

TITRATION I

TITRATION II
Burette solution

Std Sodium Hydroxide

Std Sodium Hydroxide

Pipette solution

20 ml hydrochloric acid 20 ml hydrochloric acid
Additional solution


20 ml distilled water

20 ml distilled water


End point



Sudden increase in pH
pH gradual increase

Equivalent Weight of HCl = 36.5







ROUGH GRAPH FAIR GRAPH











pH
? pH/ ? V





Volume of NaOH
(ml)
Volume of NaOH
(ml)





25



Expt. No. 4 DETERMINATION OF STRENGTH OF HCl by pH METRY

AIM
To determine the strength of given HCl by pH metry. A standard solution of 0.1N NaOH is provided.

PRINCIPLE
The pH of a solution is related to H
+
ion concentration by the following formula.

. pH = -log [ H
+
]

pH of a solution is indirectly related to H
+
ion concentration. When NaOH is added slowly to HCl, H
+
ions
get neutralized by OH
-
ions. The pH increases slowly.

H
+
+ Cl
-
+ Na
+
+ OH
-
? Na
+
+ Cl
-
+H 2O

When all H
+
ions of HCl are neutralized at the end point, addition of NaOH causes high increase in pH
because of the addition of excess OH
-
ions.

MATERIALS REQUIRED
pH meter, Glass electrode, Burette, Pipette, Std.NaOH, approximately N/10 HCl .

PROCEDURE

The burette is washed with distilled water, rinsed with the given std. Sodium hydroxide and filled with the
same solution. Exactly 10ml of the given HCl solution is pipetted out into a clean beaker. It is then diluted to 50ml
with distilled water. A glass electrode is dipped into the solution and its terminals are connected to a pH meter.

26

TITRATION - I
S.No Volume of
NaOH (ml)
pH
1

2

3

4

5

6

7

8

9

10


TITRATION - II



CALCULATION

Volume of NaOH (V 1) = ------------------- ml ( titre value)
Strength of NaOH (N 1) = ------------------- N
Volume of HCl (V 2) = ------------------ml
Strength of HCl (N 2) = ------------------ N
N 2 = V 1 N 1 / V 2
Strength of HCl = -------------------- N
Amount of HCl present in 1000ml of the given solution = Strength x equivalent weight of HCl
= ------------------ X 36.5
= --------------------- g
S.No Volume of
NaOH (ml)
pH
11

12

13

14

15

16

17

18

19

20

S.No
Volume of
NaOH (ml)
pH ?pH ?V ?pH / ?V
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
27



Now NaOH is gradually added from the burette to HCl taken in the beaker. pH of the solution is noted for
each addition of NaOH. This process is continued until 5 readings are taken after the end point.
A fair titration is performed to find the exact end point.





RESULT

(i) Strength of the given HCl solution = ---------------- N
(ii) Amount of HCl present in a litre of the solution = ---------------- g


VIVA-VOCE

1. What is meant by pH?
2. What is the name of the reference electrode used ?
3. Why does pH value increase suddenly at the end point?
4. What is the indicator used in the titration?
5. What is the pH range of human blood?
6. What is the unit of pH?
7. How will you calculate the amount of HCl?
8. How is glass electrode represented?
9. Why is glass electrode known as ion selective electrode?
10. What is the chemical reaction involved in this titration?





28




SHORT PROCEDURE


CONTENTS
TITRATION
Burette solution

Std Sodium Hydroxide

Pipette solution

20 ml mixture of acid (HCl+ CH 3COOH)


Additional solution

20 ml distilled water


End point

Conductivity decreases-slowly increases-Sudden increase



Equivalent Weight of HCl = 36.5


Equivalent Weight of CH 3COOH = 60



MODEL GRAPH


Conductance
Volume of NaOH
Mixture of Acids






29




Expt. No. 5 CONDUCTOMETRIC TITRATION OF MIXTURE
OF ACIDS

AIM
To determine the amount of a strong acid and a weak acid present in the given solution.

PRINCIPLE

Solution of electrolytes conducts electricity due to the presence of ions. Since specific conductance of a
solution is proportional to the concentration of ions in it, conductance of the solution is measured during the titration.

HCl + NaOH ? NaCl + H 2O (I neutralization)

CH 3COOH + NaOH ? CH 3COONa + H 2O (II neutralization)

When a solution of HCl is treated with NaOH the fast moving hydrogen ions are progressively replaced by
slow moving sodium ions. As a result conductance of the solution decreases. This decrease will take place until the
first neutralisation point is reached. Further addition of alkali results in formation of sodium acetate.

Since sodium acetate is stronger than acetic acid conductivity slowly increases until all acetic acid is
completely neutralized.(II Neutralisation) This is due to the presence of fast moving OH
-
ions. Anymore addition of
alkali increases the conductance sharply.

PROCEDURE
The burette is filled with NaOH solution upto zero mark. The given unknown solution (mixture of a weak &
a strong acid) is transferred into a 100ml standard flask and made upto the mark with distilled water. 20ml of the
made up solution is pipetted out into a clean 100ml beaker. The solution is diluted to 20ml using distilled water. A
conductivity cell is dipped into the solution and the terminals are connected to a conductivity meter.
30


TITRATION


CALCULATION OF STRENGTH OF HCl
Volume of NaOH (V 1) = --------------- ml (titre value)
Strength of NaOH (N 1) = ---------------- N
Volume of HCl (V 2) = ------------ ml
Strength of HCl (N 2) = -------------- N

N 2 = V 1 N 1 / V 2
Strength of HCl = ---------------- N
CALCULATION OF STRENGTH OF CH3COOH
Volume of NaOH (V 1) = ------------ ml (titre value)
Strength of NaOH (N 1) = ------------ N
Volume of CH 3COOH (V 2) = ------------ ml
Strength of CH 3COOH (N 2) = ------------ N
N 2 = V 1 N 1 / V 2

Strength of CH 3COOH = ------------ N



S.No

Volume of NaOH
(ml)

Conductance (mho)

14

15

16

17
18
19
20

21
22
23
24
25
26

S.No

Volume of NaOH
(ml)

Conductance (mho)

1
2
3
4
5
6
7
8
9
10
11
12
13
31

The burette solution is added to the unknown solution in the beaker in 0.5 ml increments, the solution is
stirred using a glass rod, and the observed conductance values are read from the meter. The conductance values
show decrease in the initial values, then gradually increases and finally shows a steep increase. The titration hence
shows two end-points (i.e) I neutralization (weak acid) & II neutralization (strong acid).
The accurate end-point is obtained by plotting a graph between observed conductance Vs volume of
NaOH added.

RESULT
The strength of acids present in the given unknown solution are:
a) Strong acid = ---------------- N
b) Weak acid = -----------------N



VIVA-VOCE

1. What is weak acid?
2. How many end points are obtained from the graph? Comment two end points.
3. Why is the conductance increase in the first end point?
4. What mixture of acids used in this titration?
5. Write the neutralization reaction between CH 3COOH and NaOH.
6. What is the solution present in the conductivity cell?
7. What are strong and weak electrolytes?
8. Give an example for strong acid and weak acid.
9. What is the strong electrolyte of weak electrolyte?
10. Give an example for strong base.









32

SHORT PROCEDURE



















ROUGH GRAPH







EMF(mV)






Volume of Potassium dichromate (ml)

FAIR GRAPH









? E / ? V

Volume of Potassium dichromate (ml)




CONTENTS

TITRATION I

TITRATION II
Burette solution

Std Potassium dichromate

Std Potassium dichromate

Pipette solution

10 ml of FAS


10 ml of FAS



Additional
solution

20 ml distilled water+
10 ml of dil H 2SO 4


20 ml distilled water+
10 ml of dil H 2SO 4

End point

Sudden increase in EMF

EMF increases and decreases

Equivalent Weight of Ferrous ion = 55.85

33


Expt. No. 6 ESTIMATION OF FERROUS ION BY POTENTIOMETRIC
TITRATION

AIM
To estimate the amount of ferrous ion present in whole of the given solution potentiometrically. A standard
solution of potassium dichromate of strength -----------N is provided.

PRINCIPLE

Potentiometric titrations depend on measurement of emf between reference electrode and an indicator
electrode. When a solution of ferrous iron is titrated with a solution of potassium dichromate, the following redox
reaction takes place.

6Fe
2+
+ Cr 2O 7
2-
+ 14 H
+
? 6Fe
3+
+ 2Cr
3+
+ 7H 2O

During this titration Fe
2+
is converted in to Fe
3+
, whose concentration increases. At the end point, there
will be a sharp change due to sudden removal of all Fe
2+
ions.
The cell is set up by connecting this redox electrode with a calomel electrode as shown below:

Pt, Fe
2+
, Fe
3+
, II KCl , HgCl 2 (s), Hg

A graph between EMF measured against the volume of potassium dichromate added is drawn and the
end point is noted from the graph.

PROCEDURE

10ml of Ferrous solution is pipetted out into a 100 ml beaker. 10ml of dil.H 2SO 4 and 20ml of distilled water
are added. A platinum electrode and a calomel electrode are dipped into this solution and connected to the
potentiometer. Then 1ml of potassium dichromate is added to the solution and stirred well for 30 seconds. The
EMF is measured and the titration is continued by adding potassium dichromate in 1ml increments till five
measurements after the end point.



34


ROUGH TITRATION



S.No.

Volume of dichromate (ml)

EMF (mV)


1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.





35







A graph is drawn by plotting the emf against the volume of potassium dichromate and the end point range is
fixed.


About 20ml of Ferrous solution is pipetted out and the titration is continued by adding 0.1ml increaments of
potassium dichromate in the end point range. The emf is measured for each 0.1ml after stirring the solution well.


A graph is plotted between emf and the volume of potassium dichromate and also a first derivative graph is
plotted ( ? E/ ? V against vol. of K 2Cr 2O 7). The strength of Ferrous solution and the amount of Ferrous ion present are
calculated from the end point.



























36

FAIR TITRATION

S.No Volume of
Dichromate (ml)
Emf (mV) ?E ?V ?E/?V






















CALCULATION

Volume of Potassim dichromate (V 1) = -------------- ml
Normality of Potassium dichromate (N 1) = --------------- N
Volume of Ferrous sulphate (V 2) = --------------- ml
Normality of Ferrous sulphate (N 2) = --------------- N
Amount of Ferrous ion present in 1000ml of the solution = Normality X Equivalent weight of ferrous ion
= --------------- X 55.85 g

The amount of Ferrous ion present in the given solution = ----------------- g






37









RESULT

The amount of Ferrous ion present in the whole of the given solution = --------------- g.








VIVA-VOCE

1. What is EMF?
2. What is the basic principle of potentiometric titration?
3. Why does EMF increase during the titration?
4. Write the cell representation of the titration.
5. What is redox reaction?
6. What is the purpose of adding sulphuric acid?
7. What are the advantages of potentiometric titration?
8. How will you obtain the end point in the titration?
9. What is the name of the indicator electrode used in this titration?
10. What is the name of the reference electrode used?








38



SHORT PROCEDURE



CONTENTS

TITRATION
Burette solution

Sodium Hydroxide

Pipette solution

20 ml HCl


Additional solution

20 ml distilled water


End point

Decrease in conductance- increase in conductance

Equivalent Weight of HCl = 36.5
















Conductance

Volume of NaOH ( ml)









39


Expt.No. 7 CONDUCTOMETRIC TITRATION OF STRONG ACID
WITH STRONG BASE
AIM

To determine the strength of a strong acid by titrating a strong acid and strong base conductometrically. A
standard solution of NaOH of known strength ---------N is provided.

PRINCIPLE
Solution of electrolytes conducts electricity due to the presence of ions. The specific conductance of a
solution is proportional to the concentration of ions in it. The reaction between HCl and NaOH may be represented
as,
HCl +NaOH ? NaCl + H 2O

When a solution of hydrochloric acid is titrated with NaOH, the fast moving hydrogen ions are
progressively replaced by slow moving sodium ions. As a result conductance of the solution decreases, this
decrease in conductance will take place until the end point is reached. Further addition of alkali raises the
conductance sharply, as there is an excess of hydroxide ions.

A graph is drawn between volume of NaOH added and the conductance of solution. The exact end point
is intersection of the two lines.

PROCEDURE

The given HCl is made up in a 100ml standard flask. 10 ml of this solution is pipetted out in a beaker. The
burette is filled with standard sodium hydroxide upto the mark.

A conductivity cell is dipped into the beaker with HCl solution and connected to the terminals of the
conductivity bridge. About 1ml of STD NaOH is added and stirred well for 30 seconds. The conductance is
measured and the titration is continued till five measurements after the endpoint. A graph is plotted for the
conductance values against the volume of NaOH and the endpoint range is fixed.

40


TABLE



CALCULATION
Volume of Sodium Hydroxide (V 1) = ------------- ml
Normality of Sodium Hydroxide (N 1) = ------------- N
Volume of Strong acid (V 2) = ------------- ml
Normality of Strong acid (N 2) = V 1 N 1
V 2

The strength of the given strong acid = ------------- N




S.NO
Volume of NaOH
(ml)
Conductance
(mho)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
41

The above titration is repeated again and the exact endpoint is found out by adding in increments of 0.1ml
of NaOH in the end point range and continued after endpoint upto five readings.
A graph is plotted with the conductance values against the volume of NaOH and then the strength of the
strong acid is found out.


RESULT

The strength of the given strong acid is found to be = --------------- N







VIVA-VOCE

1. What is the basic principle of conductometric titration?
2. Why is conductance decreased and increased during the titration?
3. What is conductance mention its unit?
4. Give some examples for Strong acids and Strong bases.
5. Write the reaction between HCl and NaOH.
6. What is meant by strong base?
7. Explain why HCl is a strong acid?
8. Explain why the strength of burette solution is always greater than the pipette solution in conductometric
titration.
9. What is the equivalent weight of HCl and NaOH?
10. Write the formula that is used to calculate the amount of HCl.











42

ESTIMATION OF COPPER

Alloy solution Vs Std. Na2S2O3 (Thio) Indicator: Starch

S.No.
Volume of
Alloy Solution
(ml)
Burette Reading (ml) Volume of
Thio
(ml)
Concordant value
(ml)
Initial Final

1.

2.

3.












CALCULATION
Volume of Na 2S 2O 3 V 1 = ------------- ml

Strength of Na 2S 2O 3 N 1 = ------------- N

Volume of brass solution V 2 = ------------- ml

Strength of brass solution N 2 = ------------- ?

= V 1 x N I / /V 2

= -------------

Strength of copper solution is = ------------- N



















43


Expt.No.8 ESTIMATION OF COPPER IN BRASS
AIM
To estimate the amount of copper present in the given sample of brass.

PRINCIPLE
Brass is an alloy with 55% copper and 33% zinc and small amount of lead and aluminum. Brass is dissolved
in conc. nitric acid to convert copper present in the alloy to cupric ions. Then copper is estimated iodometrically by
titrating the iodine that was liberated against standard sodium thio sulphate solution using starch as indicator.

2 Cu
2+
+ 4I
-
? 2 CuI + I2
I 2 + 2 Na 2S 2O 3 ? Na 2S 4O 6 + 2NaI

CHEMICALS REQUIRED
0.1N Potassium dichromate, 0.1N sodium thio sulphate, 0.01M EDTA, Con. HNO 3 , , KI, EBT,
NH 3OH / NH 4Cl buffer, Starch.

PROCEDURE
PREPARATION OF BRASS ALLOY SOLUTION

About 0.2g of the sample of brass was weighed accurately and transferred into a clean dry 250ml beaker. To
this about 10ml of con. Nitric acid was added and allowed to boil for a small interval of time till the alloy was dissolved.
This was cooled, diluted with water and made upto 250 ml in a standard flask.

TITRATION I
STANDARDIZATION OF Na2S2O3 WITH K2Cr2O7 SOLUTION
20ml of the standard potassium dichromate solution is pipetted out into a conical flask. 20ml of dil.sulphuric
acid and 10ml of 10% KI are added. The liberated iodine is titrated against sodium thio sulphate taken in the burette till
the colour changes to yellowish green. 1ml of starch is added till the colour changes from blue to light green colour.
Titration is repeated for concordance.
44



CALCULATION


Amount of copper in 1lt of given brass solution = Strength of solution x Eq. Wt of Cu


= ------------------ N x 63.5

= -------------------------

So, Amount of copper in 100ml of given brass solution = ------------------- N x 63.5 x 100 / 1000



ie, ------------g of brass contains = -------------------- g of copper


therefore, % of copper in the given brass sample = ------------------- g x 100


= ------------------ g of brass


= ------------------------ %























45


TITRATION II

ESTIMATION OF COPPER

The brass solution is transferred into the 100ml standard flask and 10ml of dil. sulphuric acid is added and
made up to the mark using distilled water.

20ml of the alloy solutionis pipetted out into a conical flask. To this aqueous ammonia is added in drops till
a blue precipitate of Cu(OH) 2 is formed. One or two drops of acetic acid is added to dissolve the precipitate. To
this 10ml of 10% KI is added and titrated against standard thio sulphate using starch as indicator. The end point is
the disappearance of blue colour and appearance of green colour.



RESULT

The given sample of brass was found to contain copper = ------------- %





VIVA-VOCE



1. What is the composition of brass?
2. What is meant by iodometry?
3. What is the principle used in t his method?
4. What is the role of K 2Cr 2O 7?
5. What is the colour change in this titration?
6. Write the chemical reactions involved in this experiments?
7. How will you find out % of copper in brass?
8. What is the role of indicator?
9. What is the equivalent weight of copper?
10. What is the role of adding aqueous ammonia?


46


SHORT PROCEDURE
Standard solutions are prepared by the dilution of the given stock solution. The flasks are numbered and
the solutions are prepared according to the following table using different glass pipettes.



Flask number

1 2 3 4 5 6
Vol. of pipette to use 1 1 2 10 10 10
Vol. of Na stock solution to pipette 0.5 1 2 4 6 8
Conc. of solution obtained (?g/ml) 5 10 10 40 60 80



MODEL GRAPH








ABSORBANCE






CONCENTRATION








47

Expt. No 9 ESTIMATION OF SODIUM BY USING
FLAME PHOTOMETER
AIM
To estimate the amount of sodium present in whole of the given solution.

APPARATUS REQUIRED
1. Flame photometer FLAPHO or Eppendorf.
2. Stock solutions of Na+ and K+, C = 1 mg/ml.
3. 6 numbered 100 ml volumetric flasks.
4. Glass pipettes: 1, 2, 10 ml.

MEASUREMENT PROCEDURE

1. The flame photo meter is switched on.
2. The instrument is kept for warming.
3. Distilled water is fed into the instrument.
4. The element Na is selected by turning the selector ?Elementwahl?.
5. The outer knob ?Messbereich? is turned into position ?100?. The ?Kompensaton I? knob is pulled slightly
out and adjusted to 0. The ?Kompensation I? knob is pressed back. 0 reading is adjusted with
?Kompensation II? if necessary.
6. The most concentrated standard solution (solution number 6) is aspirated and is adjusted to 350 (on
uppermost scale) using inner ?Messbereich? knob.
6. Distilled water is aspirated till instrument reads 0.
7. The standard solutions no. 1, 2, 3, test solution, and then standards 4, 5, 6 are aspirated.
The results are recorded.
8. Distilled water is aspirated for at least 5 minutes to clean the system(FLAPHO flame photometer).
(FLAPHO is a dual channel instrument, which measures concentrations of Na simultaneously).







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?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





3


PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)
1. Fundamentals
To provide students with a solid foundation in Mathematics, Science and fundamentals of engineering,
enabling them to apply, to find solutions for engineering problems and use this knowledge to acquire higher
education
2. Core Competence
To train the students in chemistry practicals so that they apply their knowledge and training to compare,
and to analyze various engineering industrial problems to find solutions
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice this enables
them to find solutions for the real time problems in industry, and to design products
4. Professionalism
To inculcate professional and effective communication skills, leadership qualities and team spirit in the
students to make them multi-faceted personalities and develop their ability to relate engineering issues to
broader social context
5. Lifelong Learning/Ethics
To demonstrate and practice ethical and professional responsibilities in the industry and society in the
large, through commitment and lifelong learning needed for successful professional career






4


PROGRAMME OUTCOMES (POs)
To demonstrate and apply knowledge of Mathematics, Science and engineering fundamentals in the following
experiments.
1 .To estimate HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. To determine total, temporary & permanent hardness of water by EDTA method.
3. To determine DO content of water sample by Winkler?s method.
4. To determine chloride content of water sample by Argentometric method.
5. To estimate copper content of the given solution by Iodometry.
6. To determine strength of given hydrochloric acid using pH meter.
7. To determine strength of acids in a mixture of acids using conductivity meter.
8. To determine iron content of the given solution using potentiometer.
9. To estimate iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. To estimate sodium and potassium present in water using flame photometer.
11. To determine molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. To determine Pseudo first order kinetics ? ester hydrolysis.
13. To determine Corrosion experiment ? weight loss method.
14. To estimate CMC.
15. To estimate Phase change in a solid.
16. To determine strength of strong acid vs strong base using conductivity meter.











5

BS8161 - CHEMISTRY LABORATORY
SYLLABUS


? To make the student to acquire practical skills in the determination of water quality
parameters through volumetric and instrumental analysis.

? ???? ??? ???? ?? ???? ? ? ?To acquaint the students with the determination of molecular weight of a polymer by
viscometery.

LIST OF EXPERIMENTS:
1. Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. Determination of total, temporary & permanent hardness of water by EDTA method.
3. Determination of DO content of water sample by Winkler?s method.
4. Determination of chloride content of water sample by Argentometric method.
5. Estimation of copper content of the given solution by Iodometry.
6. Determination of strength of given hydrochloric acid using pH meter.
7. Determination of strength of acids in a mixture of acids using conductivity meter.
8. Estimation of iron content of the given solution using potentiometer.
9. Estimation of iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. Estimation of sodium and potassium present in water using flame photometer.
11. Determination of molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. Pseudo first order kinetics ? ester hydrolysis.
13. Corrosion experiment ? weight loss method.
14. Determination of CMC.
15. Phase change in a solid.
16. Conductometric titration of strong acid vs strong base.




? The students will be outfitted with hands-on knowledge in the quantitative chemical
analysis of water quality related parameters.
COURSE OBJECTIVES
COURSE OUTCOMES
6


INDEX [ SEMESTER ? I ]


S.No.



Date


Experiment

Date of
submission



Mark


Signature

1.

Estimation of HCl using Na 2CO 3 as
primary standard and Determination of
alkalinity in water sample.



2.


Determination of total, temporary &
permanent hardness of water by EDTA
method.



3.


Determination of chloride content of water
sample by argentometric method.



4.


Determination of strength of given
hydrochloric acid using pH meter.



5.


Determination of strength of acids in a
mixture of acids using conductivity meter.



6.


Estimation of iron content of the given
solution using potentiometer.



7.





Conductometric titration of strong acid Vs
strong base.



8.



Estimation of copper content of the given
solution by Iodometry


9.
Estimation of sodium and potassium
present in water using flame photometer




7




CONTENTS


S.No.


NAME OF EXPERIMENT

PAGE
No.
SEMESTER - I
1.
Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in
water sample.
09
2. Determination of total, temporary & permanent hardness of water by EDTA method. 15
3. Determination of chloride content of water sample by Argentometric method. 21
4. Determination of strength of given hydrochloric acid using pH meter. 25
5. Determination of strength of acids in a mixture of acids using conductivity meter. 29
6. Estimation of iron content of the given solution using potentiometer. 33
7. Conductometric titration of strong acid Vs strong base.

39


42

8


Estimation of copper content of the given solution by Iodometry 43
9 Estimation of sodium and potassium present in water using flame photometer 47






8



SHORT PROCEDURE:

CONTENTS
TITRATION
Estimation of alkalinity in water sample
(Std HCl Vs water sample)

Burette solution

Std. HCl


Pipette solution

Water sample


Indicator


(i) Phenolphthalein
(ii) Methyl orange


End point

(i) Disappearance of pink colour
(ii) Appearance of reddish orange colour






Relationship
between P &M
Nature of alkalinity
Amount of individual
alkalinities
OH
-
HCO 3
-


CO 3
2-

P = M

only OH
-

P or M

?
0.0

0.0


2P = M

only CO 3
2-


2P or M


0.0


0.0


?

P =0, M?0

only HCO 3
-



M



0.0



?

0.0


2P > M


OH
-
&CO 3
2-


OH
-
= 2P-M
CO 3
2-
= 2(M-P)


?

0.0

?

P < ? M




HCO 3
-
&CO 3
2-


HCO 3
-
= M-2P
CO 3
2-
= 2P

0.0 ? ?




9





Expt. No. 1 DETERMINATION OF ALKALINITY IN WATER
AIM
To determine the type and amounts of alkalinity in the given water sample. A standard solution of Na 2CO 3
of strength ____N is given.

PRINCIPLE
Alkalinity in water is due to the presence of soluble hydroxides, bicarbonates and carbonates.
Determination of various types and amounts of alkalinity is easily carried out by titration with standard HCl
employing the indicators phenolphthalein and methyl orange independently or in succession.

The following reactions occur when different types of alkalinity are neutralized with acid.

OH
?
+ H
+
? H 2O completed at pH 8.2-9.0 ----- (1)

CO 3
2 ?
+ H
+
? HCO 3
?
----- (2)

HCO 3
?
+ H
+
? (H 2CO 3) ? H 2O + CO 2, completed at pH 4.2-5.5 ----- (3)

Neutralisation (1) & (2) will be notified by phenolphthalein end-point while all the three will be

accounted by
methyl orange end-point. Bicarbonate in eqn. (3) may be due to the existence of soluble free bicarbonate salts and
bicarbonates resulting from half neutralization of soluble carbonates (eqn. (2))

Various steps to be followed

a) A known volume of water sample is titrated against std. HCl using first phenolphthalein indicator till
end-point (P) and the titration is continued without break using methyl orange indicator till the end-
point (M).



10


Titration

Estimation of Alkalinity in water sample

Standard HCl Vs Water sample Indicator: 1. Phenolphthalein
2. Methyl Orange


S.No.
Volume
of water
sample (ml)
Burette Reading
Concordant value

Initial Phenolphthalein End
Point (P)
Methyl Orange End
Point (M)

1

2






CALCULATION

Hydroxide ion alkalinity
Volume of HCl (2P-M) = ???????ml

Strength of HCl = ???????? N

Volume of water sample = ???????...ml

Strength of water sample = Volume of HCl (2P-M) x Strength of HCl
Volume of water sample

=

? Hydroxide ion alkalinity in terms of
CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ??????.mg/l







11




b) From the magnitudes of the P & M, the nature of alkalinity can be arrived as follows:

(i) P = M => Presence of only OH
-

(ii) 2P = M => Presence of only CO 3
2-

(iii) P =0, M=0 => Presence of only HCO 3
-
(iv) 2P > M => Presence of OH
-
& CO 3
2-
(v) 2P < M => Presence of HCO 3
-
& CO 3
2-

(Mixture of OH
-
& HCO3
-
is not listed since they do not exist together and are considered equivalent to CO 3
2-
).

PROCEDURE
TITRATION
ESTIMATION OF ALKALINITY IN WATER SAMPLE

Exactly 20 ml of water sample is pipetted out into a clean conical flask. Few drops of phenolphthalein
indicator are added and titrated against a standardized HCl taken in the burette. The end point is the
disappearance of pink colour, which is noted as P. Few drops of methyl orange indicator is added to the same
solution. The solution turns to yellow. The titration is continued further by adding same HCl without break till the
end point is reached. The end point is the colour change from yellow to reddish orange.

The experiment is repeated to get concordant values. From the magnitudes of P & M values, the type of
alkalinity present in the water sample is inferred and the individual amounts are calculated and reported.










12


Carbonate ion alkalinity

Volume of HCl 2 (M ? P) = ??? ????????ml

Strength of HCl = ??.?????..???...N

Volume of water sample =........................................ml

Strength of water sample = Volume of HCl 2 (M ? P) x Strength of HCl
Volume of water sample

= ???????????.. N




? Carbonate ion alkalinity
in terms of CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ???????????mg/l

















13





RESULT

1) The type of alkalinity present in the water sample = -------------------------ions.

2) The individual amounts of alkalinity present in the water sample:
Hydroxide ion alkalinity

= ----------------- ppm
Carbonate ion alkalinity = ------------------ ppm
Bicarbonate ion alkalinity = ----------------- ppm





VIVA-VOCE


1. What is meant by alkalinity?
2. What are the ions responsible for alkalinity?
3. Why OH
-
and HCO 3
?
ions cannot exist together in water?
4. What are the ions responsible for alkalinity when 2P > M?
5. What is the pH range for both in acidic and basic solutions?
6. What is the colour of phenolphthalein in an acid and in an alkaline solution?
7. What is the purpose of using two indicators in same titration?
8. What are the possible combinations of ions for alkalinity?
9. How is the amount of alkalinity expressed?
10. What are the types of indicator used in this experiment?







14

SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II TITRATION III
Standardisation of
EDTA
(EDTA Vs Std
Hard water)
Determination of
total hardness
(Std EDTA Vs Hard
water sample)
Determination of
permanent hardness
(Std EDTA Vs Boiled
Hard water sample)

Burette solution

EDTA solution

EDTA solution

EDTA solution

Pipette solution

20ml Std. hard water

20 ml hard water sample

20ml boiled hard water sample

Indicator

2 drops of EBT

2 drops of EBT

2 drops of EBT

Additional soln.


Ammoniacal Buffer
solution (5ml)

Ammoniacal Buffer solution
(5ml)

Ammoniacal Buffer solution
(5ml)
End point Wine - red to Steel blue Wine - red to steel blue Wine - red to Steel blue




STANDARDISATION OF EDTA
Titration - I
Std. HARD WATER Vs EDTA Indicator: EBT

S. No.
Volume of std hard
water (ml)
Burette Reading Volume of
EDTA
(V 1) (ml)
Concordant value

Initial

Final



Volume of std .hard water taken = 20 ml
Volume of EDTA consumed (V 1) = --------------- ml
1 ml of std.hard water = 1mg of CaCO 3
20 ml of std hard water = 20 mg of CaCO 3

V 1 ml of EDTA solution containing 20 mg of CaCO 3
1 ml of EDTA solution = 20 / V 1 mg of CaCO 3
= -----------------------mg of CaCO 3


15

Expt. No. 2 DETERMINATION OF TOTAL, TEMPORARY AND
PERMANENT HARDNESS OF WATER

AIM
To estimate the amount of total, temporary & permanent hardness in the given sample of water.

PRINCIPLE
The estimation is based on the complexometric titration.

(i) Total hardness of water is estimated by titrating against EDTA using EBT indicator.
EBT+M ?[EBT-M] (unstable complex)
(EBT-M) (Unstable complex) +EDTA ? [EDTA-M] (stable complex) +EBT
EBT indicator forms wine- red colored complex with metal ions present in water. On addition of EDTA
metal ions preferably forms complexes with EDTA and steel blue EBT indicator is set free. Therefore
change of colour from wine- red to steel blue denotes the end point.

(ii) Temporary hardness is removed by boiling the water.
Ca (HCO 3) 2 ? CaCO 3 +CO 2 ?+H 2O
Mg (HCO 3) 2 ? Mg(OH) 2 +2CO 2 ?
The precipitate is filtered and the remaining permanent hardness is estimated using EDTA.

PROCEDURE

TITRATION ? I
STANDARDISATION OF EDTA

Pipette out 20ml of standard hard water into a 250ml conical flask. Add 5ml of buffer solution and 3
drops of eriochrome black T indictor. Titrate the solution with EDTA from the burette until the colour
changes from wine- red to steel blue at the end point. Repeat the titration for concordant values. Let the
titre value be V 1ml.


16


Titration-II
SAMPLE HARD WATER Vs Std EDTA Indicator: EBT

S.No. Volume of sample
hard water (ml)
Burette Reading Volume of
EDTA
(V 2) (ml)
Concordant value

Initial

Final




CALCULATION

Calculation of total hardness


Volume of EDTA consumed (V 2) = ------------------------- ml
1ml of EDTA = 20 / V 1 mg of CaCO 3
V 2 ml of EDTA = 20 / V 1 x V 2 mg of CaCO 3

( i.e), If 20ml of sample hard water contains 20 x V 2 mg of CaCO 3 / V 1

Then 1000ml of water sample = 20 x V 2 x 1000 / V 1 x 20 mg of CaCO 3

= 1000 x V 2 / V 1 mg of CaCO3

Total hardness of given water sample = ---------------------ppm









17



DETERMINATION OF TOTAL HARDNESS

Pipette out 20ml of sample hard water into a clean conical flask. Add 5ml of buffer solution and 4 -5
drops of Eriochrome black -T indicator. Titrate the wine - red coloured solution with EDTA from the burette until
the colour steel blue appears at the end point. Repeat the titration for concordant values. Let the titre value be
V 2ml.



DETERMINATION OF PERMANENT HARDNESS

Take 100ml of hard water sample in a 500ml beaker and boil gently for about 1hour. Cool, filter it into a
100ml standard flask and make the volume up to the mark. Take 20ml of this solution and proceed it in the same
way as in titration (I). The volume of EDTA consumed corresponds to the permanent hardness of the water
sample. Let the titre value be V 3ml. Temporary hardness is calculated by subtracting permanent hardness from
total hardness.





















18




DETERMINATION OF PERMANENT HARDNESS
BOILED SAMPLE WATER Vs Std. EDTA Indicator: EBT


S.No.
Volume of boiled
hard water (ml)
Burette Reading (ml) Volume of
EDTA
(ml)

Concordant value

Initial Final



CALCULATION OF PERMANENT HARDNESS


Volume of EDTA consumed V 3 = ---------------------ml

1ml of EDTA = 20 / V 1 mg of CaCO 3

V 3ml of EDTA = 20 / V 1 x V 3 mg of CaCO 3

(i.e) 20 ml of boiled sample hard water = 20 / V 1 x V 3 mg of CaCO 3

Then 1000ml of boiled water sample = 20 / V 1 x V 3 / 20 * 1000mg of CaCO 3

= 1000 x V 3 / V 1 mg of CaCO 3

permanent hardness of boiled water sample = -----------------ppm

Temporary hardness of the given water sample = Total hardness ? Permanent hardness

= ------------------ppm

19







RESULT

(i) Total hardness of the given sample water = -------------- ppm.
(ii) Permanent hardness of the given sample water = --------------- ppm.
(iii) Temporary hardness of the given sample water = ----------------ppm.







VIVA-VOCE

1. Define ? Hard water
2. What is the structure of EDTA?
3. How will you calculate temporary hardness?
4. What is the role of the buffer in EDTA titration?
5. What is the permissible limit of hardness in drinking water?
6. Name the hardness producing ions present in water.
7. Name two salts which are responsible for temporary hardness.
8. Why is CaCO 3 taken as the standard?
9. Write the expansion of EDTA.
10. What is meant by EBT?











20





SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II
Standardisation of
AgNO 3
Estimation of Chloride
Burette solution

AgNO 3 solution

Std. AgNO 3 solution

Pipette solution

20ml std KCl solution

20 ml water sample

Indicator

1ml K 2CrO 4

1ml K 2CrO 4


End point

yellow to reddish brown

yellow to reddish brown

Titration I
Std. AgNO3 Vs KCl Indicator: Potassium Chromate













CALCULATION

Volume of KCl (V 1) = ------- ml

Strength of KCl (N 1) = ------- N

Volume of Silver Nitrate (V 2) = -------- ml

Strength of Siver Nitrate V 1N 1
N 2 =
V 1

= --------------------- N

S.No.
Volume of KCl
(ml)
Burette Reading (ml)
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

21




Expt.No. 3 ESTIMATION OF CHLORIDE CONTENT IN WATER
(ARGENTOMETRIC METHOD)
AIM
To estimate the amount of chloride present in given water sample by Argentometric method (Mohr?s
method). You are provided with standard solution of NaCl of strength --------N and a approximately N/10 solution of
Silver nitrate.

PRINCIPLE
The Chloride ion in the form of NaCl, KCl, CaCl 2, MgCl 2 etc., present in the water sample can be estimated
by Argentometric method or known as Mohr?s method. It is an example for precipitation titration. The reaction
between std. Sodium chloride and Silver nitrate is given below.
AgNO 3 + NaCl ? AgCl ? + NaNO 3
The completion of reaction can be observed by employing potassium chromate as the indicator. The end
point is the colour change from yellow to reddish brown due to the following reaction.
2AgNO 3 + K 2CrO 4 ? Ag 2CrO 4 ? + 2KNO 3
Potassium chromate indicator will not be precipitated as silver chromate until all the chlorides in the solution
have been precipitated as AgCl Since a precipitation reaction takes place in preference, this reaction takes place
only at the end point.

PROCEDURE
TITRATION I: STANDARDISATION OF SILVER NITRATE
Pipette out 20ml of standard sodium or potassium chloride solution into a clean conical flask. Add 1ml of 5%
K 2CrO 4 indicator, as the solution turns yellow in colour. Titrate it against silver nitrate solution taken in the burette.
Observe the nearness of the end point through the formation of coagulated silver chloride precipitate at the bottom
of the flask. Now add the silver nitrate drop by drop until the solution gets a faint reddish brown tinge. Repeat the
titration for concordant value. Let the volume of silver nitrate be V 2ml.





22






TITRATION - II

Std AgNO3 Vs WATER SAMPLE Indicator: Potassium Chromate













CALCULATION

Volume of Silver Nitrate (V 3) = ------------ ml

Strength of Siver Nitrate (N 3) = ------------- N

Volume of Water sample (V 4) = -------------- ml

Strength of Water sample V 3 N 3
(N 4) =
V 4

= ----------------- N

Amount of Chloride ion present in 1000 ml of the water sample = Equivalent mass of HCl X 1000


= N 4 x 35.46 x 1000


= -----------------mg/l







S.No.
Volume of water
sample (ml)
Burette Reading
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

23





TITRATION - II
ESTIMATION OF CHLORIDE ION

Pipette out 40 ml of the given water sample into a clean conical flask.To this sample add 1ml of 5% K 2CrO 4
indicator and titrate it against the standardized silver nitrate solution taken in the burette and continue the titration
until the solution produces a reddish brown colour. Note down the end point and repeat the titration for
concordance. Let the volume be V 3ml.







RESULT

The amount of chloride ion present in the water sample = ----------------- mg/l.




VIVA-VOCE

1. Why is this method known as Argentometric method?
2.
What is the chemical reaction between AgNO 3 and Cl
-
ions present in water?

3.
What is the form of Chloride ion present in water?

4. What is the reaction between AgNO 3 and K 2CrO 4 ?
5. What is the name of the method used in this titration?
6. Name the link solution used in the determination.
7. Name the solution used to standardize AgNO 3.
8. What is the indicator used in the determination?
9. How will you calculate the amount of chloride ion in the given solution?
10. What is the colour change in the titration?




24




SHORT PROCEDURE


CONTENTS

TITRATION I

TITRATION II
Burette solution

Std Sodium Hydroxide

Std Sodium Hydroxide

Pipette solution

20 ml hydrochloric acid 20 ml hydrochloric acid
Additional solution


20 ml distilled water

20 ml distilled water


End point



Sudden increase in pH
pH gradual increase

Equivalent Weight of HCl = 36.5







ROUGH GRAPH FAIR GRAPH











pH
? pH/ ? V





Volume of NaOH
(ml)
Volume of NaOH
(ml)





25



Expt. No. 4 DETERMINATION OF STRENGTH OF HCl by pH METRY

AIM
To determine the strength of given HCl by pH metry. A standard solution of 0.1N NaOH is provided.

PRINCIPLE
The pH of a solution is related to H
+
ion concentration by the following formula.

. pH = -log [ H
+
]

pH of a solution is indirectly related to H
+
ion concentration. When NaOH is added slowly to HCl, H
+
ions
get neutralized by OH
-
ions. The pH increases slowly.

H
+
+ Cl
-
+ Na
+
+ OH
-
? Na
+
+ Cl
-
+H 2O

When all H
+
ions of HCl are neutralized at the end point, addition of NaOH causes high increase in pH
because of the addition of excess OH
-
ions.

MATERIALS REQUIRED
pH meter, Glass electrode, Burette, Pipette, Std.NaOH, approximately N/10 HCl .

PROCEDURE

The burette is washed with distilled water, rinsed with the given std. Sodium hydroxide and filled with the
same solution. Exactly 10ml of the given HCl solution is pipetted out into a clean beaker. It is then diluted to 50ml
with distilled water. A glass electrode is dipped into the solution and its terminals are connected to a pH meter.

26

TITRATION - I
S.No Volume of
NaOH (ml)
pH
1

2

3

4

5

6

7

8

9

10


TITRATION - II



CALCULATION

Volume of NaOH (V 1) = ------------------- ml ( titre value)
Strength of NaOH (N 1) = ------------------- N
Volume of HCl (V 2) = ------------------ml
Strength of HCl (N 2) = ------------------ N
N 2 = V 1 N 1 / V 2
Strength of HCl = -------------------- N
Amount of HCl present in 1000ml of the given solution = Strength x equivalent weight of HCl
= ------------------ X 36.5
= --------------------- g
S.No Volume of
NaOH (ml)
pH
11

12

13

14

15

16

17

18

19

20

S.No
Volume of
NaOH (ml)
pH ?pH ?V ?pH / ?V
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
27



Now NaOH is gradually added from the burette to HCl taken in the beaker. pH of the solution is noted for
each addition of NaOH. This process is continued until 5 readings are taken after the end point.
A fair titration is performed to find the exact end point.





RESULT

(i) Strength of the given HCl solution = ---------------- N
(ii) Amount of HCl present in a litre of the solution = ---------------- g


VIVA-VOCE

1. What is meant by pH?
2. What is the name of the reference electrode used ?
3. Why does pH value increase suddenly at the end point?
4. What is the indicator used in the titration?
5. What is the pH range of human blood?
6. What is the unit of pH?
7. How will you calculate the amount of HCl?
8. How is glass electrode represented?
9. Why is glass electrode known as ion selective electrode?
10. What is the chemical reaction involved in this titration?





28




SHORT PROCEDURE


CONTENTS
TITRATION
Burette solution

Std Sodium Hydroxide

Pipette solution

20 ml mixture of acid (HCl+ CH 3COOH)


Additional solution

20 ml distilled water


End point

Conductivity decreases-slowly increases-Sudden increase



Equivalent Weight of HCl = 36.5


Equivalent Weight of CH 3COOH = 60



MODEL GRAPH


Conductance
Volume of NaOH
Mixture of Acids






29




Expt. No. 5 CONDUCTOMETRIC TITRATION OF MIXTURE
OF ACIDS

AIM
To determine the amount of a strong acid and a weak acid present in the given solution.

PRINCIPLE

Solution of electrolytes conducts electricity due to the presence of ions. Since specific conductance of a
solution is proportional to the concentration of ions in it, conductance of the solution is measured during the titration.

HCl + NaOH ? NaCl + H 2O (I neutralization)

CH 3COOH + NaOH ? CH 3COONa + H 2O (II neutralization)

When a solution of HCl is treated with NaOH the fast moving hydrogen ions are progressively replaced by
slow moving sodium ions. As a result conductance of the solution decreases. This decrease will take place until the
first neutralisation point is reached. Further addition of alkali results in formation of sodium acetate.

Since sodium acetate is stronger than acetic acid conductivity slowly increases until all acetic acid is
completely neutralized.(II Neutralisation) This is due to the presence of fast moving OH
-
ions. Anymore addition of
alkali increases the conductance sharply.

PROCEDURE
The burette is filled with NaOH solution upto zero mark. The given unknown solution (mixture of a weak &
a strong acid) is transferred into a 100ml standard flask and made upto the mark with distilled water. 20ml of the
made up solution is pipetted out into a clean 100ml beaker. The solution is diluted to 20ml using distilled water. A
conductivity cell is dipped into the solution and the terminals are connected to a conductivity meter.
30


TITRATION


CALCULATION OF STRENGTH OF HCl
Volume of NaOH (V 1) = --------------- ml (titre value)
Strength of NaOH (N 1) = ---------------- N
Volume of HCl (V 2) = ------------ ml
Strength of HCl (N 2) = -------------- N

N 2 = V 1 N 1 / V 2
Strength of HCl = ---------------- N
CALCULATION OF STRENGTH OF CH3COOH
Volume of NaOH (V 1) = ------------ ml (titre value)
Strength of NaOH (N 1) = ------------ N
Volume of CH 3COOH (V 2) = ------------ ml
Strength of CH 3COOH (N 2) = ------------ N
N 2 = V 1 N 1 / V 2

Strength of CH 3COOH = ------------ N



S.No

Volume of NaOH
(ml)

Conductance (mho)

14

15

16

17
18
19
20

21
22
23
24
25
26

S.No

Volume of NaOH
(ml)

Conductance (mho)

1
2
3
4
5
6
7
8
9
10
11
12
13
31

The burette solution is added to the unknown solution in the beaker in 0.5 ml increments, the solution is
stirred using a glass rod, and the observed conductance values are read from the meter. The conductance values
show decrease in the initial values, then gradually increases and finally shows a steep increase. The titration hence
shows two end-points (i.e) I neutralization (weak acid) & II neutralization (strong acid).
The accurate end-point is obtained by plotting a graph between observed conductance Vs volume of
NaOH added.

RESULT
The strength of acids present in the given unknown solution are:
a) Strong acid = ---------------- N
b) Weak acid = -----------------N



VIVA-VOCE

1. What is weak acid?
2. How many end points are obtained from the graph? Comment two end points.
3. Why is the conductance increase in the first end point?
4. What mixture of acids used in this titration?
5. Write the neutralization reaction between CH 3COOH and NaOH.
6. What is the solution present in the conductivity cell?
7. What are strong and weak electrolytes?
8. Give an example for strong acid and weak acid.
9. What is the strong electrolyte of weak electrolyte?
10. Give an example for strong base.









32

SHORT PROCEDURE



















ROUGH GRAPH







EMF(mV)






Volume of Potassium dichromate (ml)

FAIR GRAPH









? E / ? V

Volume of Potassium dichromate (ml)




CONTENTS

TITRATION I

TITRATION II
Burette solution

Std Potassium dichromate

Std Potassium dichromate

Pipette solution

10 ml of FAS


10 ml of FAS



Additional
solution

20 ml distilled water+
10 ml of dil H 2SO 4


20 ml distilled water+
10 ml of dil H 2SO 4

End point

Sudden increase in EMF

EMF increases and decreases

Equivalent Weight of Ferrous ion = 55.85

33


Expt. No. 6 ESTIMATION OF FERROUS ION BY POTENTIOMETRIC
TITRATION

AIM
To estimate the amount of ferrous ion present in whole of the given solution potentiometrically. A standard
solution of potassium dichromate of strength -----------N is provided.

PRINCIPLE

Potentiometric titrations depend on measurement of emf between reference electrode and an indicator
electrode. When a solution of ferrous iron is titrated with a solution of potassium dichromate, the following redox
reaction takes place.

6Fe
2+
+ Cr 2O 7
2-
+ 14 H
+
? 6Fe
3+
+ 2Cr
3+
+ 7H 2O

During this titration Fe
2+
is converted in to Fe
3+
, whose concentration increases. At the end point, there
will be a sharp change due to sudden removal of all Fe
2+
ions.
The cell is set up by connecting this redox electrode with a calomel electrode as shown below:

Pt, Fe
2+
, Fe
3+
, II KCl , HgCl 2 (s), Hg

A graph between EMF measured against the volume of potassium dichromate added is drawn and the
end point is noted from the graph.

PROCEDURE

10ml of Ferrous solution is pipetted out into a 100 ml beaker. 10ml of dil.H 2SO 4 and 20ml of distilled water
are added. A platinum electrode and a calomel electrode are dipped into this solution and connected to the
potentiometer. Then 1ml of potassium dichromate is added to the solution and stirred well for 30 seconds. The
EMF is measured and the titration is continued by adding potassium dichromate in 1ml increments till five
measurements after the end point.



34


ROUGH TITRATION



S.No.

Volume of dichromate (ml)

EMF (mV)


1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.





35







A graph is drawn by plotting the emf against the volume of potassium dichromate and the end point range is
fixed.


About 20ml of Ferrous solution is pipetted out and the titration is continued by adding 0.1ml increaments of
potassium dichromate in the end point range. The emf is measured for each 0.1ml after stirring the solution well.


A graph is plotted between emf and the volume of potassium dichromate and also a first derivative graph is
plotted ( ? E/ ? V against vol. of K 2Cr 2O 7). The strength of Ferrous solution and the amount of Ferrous ion present are
calculated from the end point.



























36

FAIR TITRATION

S.No Volume of
Dichromate (ml)
Emf (mV) ?E ?V ?E/?V






















CALCULATION

Volume of Potassim dichromate (V 1) = -------------- ml
Normality of Potassium dichromate (N 1) = --------------- N
Volume of Ferrous sulphate (V 2) = --------------- ml
Normality of Ferrous sulphate (N 2) = --------------- N
Amount of Ferrous ion present in 1000ml of the solution = Normality X Equivalent weight of ferrous ion
= --------------- X 55.85 g

The amount of Ferrous ion present in the given solution = ----------------- g






37









RESULT

The amount of Ferrous ion present in the whole of the given solution = --------------- g.








VIVA-VOCE

1. What is EMF?
2. What is the basic principle of potentiometric titration?
3. Why does EMF increase during the titration?
4. Write the cell representation of the titration.
5. What is redox reaction?
6. What is the purpose of adding sulphuric acid?
7. What are the advantages of potentiometric titration?
8. How will you obtain the end point in the titration?
9. What is the name of the indicator electrode used in this titration?
10. What is the name of the reference electrode used?








38



SHORT PROCEDURE



CONTENTS

TITRATION
Burette solution

Sodium Hydroxide

Pipette solution

20 ml HCl


Additional solution

20 ml distilled water


End point

Decrease in conductance- increase in conductance

Equivalent Weight of HCl = 36.5
















Conductance

Volume of NaOH ( ml)









39


Expt.No. 7 CONDUCTOMETRIC TITRATION OF STRONG ACID
WITH STRONG BASE
AIM

To determine the strength of a strong acid by titrating a strong acid and strong base conductometrically. A
standard solution of NaOH of known strength ---------N is provided.

PRINCIPLE
Solution of electrolytes conducts electricity due to the presence of ions. The specific conductance of a
solution is proportional to the concentration of ions in it. The reaction between HCl and NaOH may be represented
as,
HCl +NaOH ? NaCl + H 2O

When a solution of hydrochloric acid is titrated with NaOH, the fast moving hydrogen ions are
progressively replaced by slow moving sodium ions. As a result conductance of the solution decreases, this
decrease in conductance will take place until the end point is reached. Further addition of alkali raises the
conductance sharply, as there is an excess of hydroxide ions.

A graph is drawn between volume of NaOH added and the conductance of solution. The exact end point
is intersection of the two lines.

PROCEDURE

The given HCl is made up in a 100ml standard flask. 10 ml of this solution is pipetted out in a beaker. The
burette is filled with standard sodium hydroxide upto the mark.

A conductivity cell is dipped into the beaker with HCl solution and connected to the terminals of the
conductivity bridge. About 1ml of STD NaOH is added and stirred well for 30 seconds. The conductance is
measured and the titration is continued till five measurements after the endpoint. A graph is plotted for the
conductance values against the volume of NaOH and the endpoint range is fixed.

40


TABLE



CALCULATION
Volume of Sodium Hydroxide (V 1) = ------------- ml
Normality of Sodium Hydroxide (N 1) = ------------- N
Volume of Strong acid (V 2) = ------------- ml
Normality of Strong acid (N 2) = V 1 N 1
V 2

The strength of the given strong acid = ------------- N




S.NO
Volume of NaOH
(ml)
Conductance
(mho)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
41

The above titration is repeated again and the exact endpoint is found out by adding in increments of 0.1ml
of NaOH in the end point range and continued after endpoint upto five readings.
A graph is plotted with the conductance values against the volume of NaOH and then the strength of the
strong acid is found out.


RESULT

The strength of the given strong acid is found to be = --------------- N







VIVA-VOCE

1. What is the basic principle of conductometric titration?
2. Why is conductance decreased and increased during the titration?
3. What is conductance mention its unit?
4. Give some examples for Strong acids and Strong bases.
5. Write the reaction between HCl and NaOH.
6. What is meant by strong base?
7. Explain why HCl is a strong acid?
8. Explain why the strength of burette solution is always greater than the pipette solution in conductometric
titration.
9. What is the equivalent weight of HCl and NaOH?
10. Write the formula that is used to calculate the amount of HCl.











42

ESTIMATION OF COPPER

Alloy solution Vs Std. Na2S2O3 (Thio) Indicator: Starch

S.No.
Volume of
Alloy Solution
(ml)
Burette Reading (ml) Volume of
Thio
(ml)
Concordant value
(ml)
Initial Final

1.

2.

3.












CALCULATION
Volume of Na 2S 2O 3 V 1 = ------------- ml

Strength of Na 2S 2O 3 N 1 = ------------- N

Volume of brass solution V 2 = ------------- ml

Strength of brass solution N 2 = ------------- ?

= V 1 x N I / /V 2

= -------------

Strength of copper solution is = ------------- N



















43


Expt.No.8 ESTIMATION OF COPPER IN BRASS
AIM
To estimate the amount of copper present in the given sample of brass.

PRINCIPLE
Brass is an alloy with 55% copper and 33% zinc and small amount of lead and aluminum. Brass is dissolved
in conc. nitric acid to convert copper present in the alloy to cupric ions. Then copper is estimated iodometrically by
titrating the iodine that was liberated against standard sodium thio sulphate solution using starch as indicator.

2 Cu
2+
+ 4I
-
? 2 CuI + I2
I 2 + 2 Na 2S 2O 3 ? Na 2S 4O 6 + 2NaI

CHEMICALS REQUIRED
0.1N Potassium dichromate, 0.1N sodium thio sulphate, 0.01M EDTA, Con. HNO 3 , , KI, EBT,
NH 3OH / NH 4Cl buffer, Starch.

PROCEDURE
PREPARATION OF BRASS ALLOY SOLUTION

About 0.2g of the sample of brass was weighed accurately and transferred into a clean dry 250ml beaker. To
this about 10ml of con. Nitric acid was added and allowed to boil for a small interval of time till the alloy was dissolved.
This was cooled, diluted with water and made upto 250 ml in a standard flask.

TITRATION I
STANDARDIZATION OF Na2S2O3 WITH K2Cr2O7 SOLUTION
20ml of the standard potassium dichromate solution is pipetted out into a conical flask. 20ml of dil.sulphuric
acid and 10ml of 10% KI are added. The liberated iodine is titrated against sodium thio sulphate taken in the burette till
the colour changes to yellowish green. 1ml of starch is added till the colour changes from blue to light green colour.
Titration is repeated for concordance.
44



CALCULATION


Amount of copper in 1lt of given brass solution = Strength of solution x Eq. Wt of Cu


= ------------------ N x 63.5

= -------------------------

So, Amount of copper in 100ml of given brass solution = ------------------- N x 63.5 x 100 / 1000



ie, ------------g of brass contains = -------------------- g of copper


therefore, % of copper in the given brass sample = ------------------- g x 100


= ------------------ g of brass


= ------------------------ %























45


TITRATION II

ESTIMATION OF COPPER

The brass solution is transferred into the 100ml standard flask and 10ml of dil. sulphuric acid is added and
made up to the mark using distilled water.

20ml of the alloy solutionis pipetted out into a conical flask. To this aqueous ammonia is added in drops till
a blue precipitate of Cu(OH) 2 is formed. One or two drops of acetic acid is added to dissolve the precipitate. To
this 10ml of 10% KI is added and titrated against standard thio sulphate using starch as indicator. The end point is
the disappearance of blue colour and appearance of green colour.



RESULT

The given sample of brass was found to contain copper = ------------- %





VIVA-VOCE



1. What is the composition of brass?
2. What is meant by iodometry?
3. What is the principle used in t his method?
4. What is the role of K 2Cr 2O 7?
5. What is the colour change in this titration?
6. Write the chemical reactions involved in this experiments?
7. How will you find out % of copper in brass?
8. What is the role of indicator?
9. What is the equivalent weight of copper?
10. What is the role of adding aqueous ammonia?


46


SHORT PROCEDURE
Standard solutions are prepared by the dilution of the given stock solution. The flasks are numbered and
the solutions are prepared according to the following table using different glass pipettes.



Flask number

1 2 3 4 5 6
Vol. of pipette to use 1 1 2 10 10 10
Vol. of Na stock solution to pipette 0.5 1 2 4 6 8
Conc. of solution obtained (?g/ml) 5 10 10 40 60 80



MODEL GRAPH








ABSORBANCE






CONCENTRATION








47

Expt. No 9 ESTIMATION OF SODIUM BY USING
FLAME PHOTOMETER
AIM
To estimate the amount of sodium present in whole of the given solution.

APPARATUS REQUIRED
1. Flame photometer FLAPHO or Eppendorf.
2. Stock solutions of Na+ and K+, C = 1 mg/ml.
3. 6 numbered 100 ml volumetric flasks.
4. Glass pipettes: 1, 2, 10 ml.

MEASUREMENT PROCEDURE

1. The flame photo meter is switched on.
2. The instrument is kept for warming.
3. Distilled water is fed into the instrument.
4. The element Na is selected by turning the selector ?Elementwahl?.
5. The outer knob ?Messbereich? is turned into position ?100?. The ?Kompensaton I? knob is pulled slightly
out and adjusted to 0. The ?Kompensation I? knob is pressed back. 0 reading is adjusted with
?Kompensation II? if necessary.
6. The most concentrated standard solution (solution number 6) is aspirated and is adjusted to 350 (on
uppermost scale) using inner ?Messbereich? knob.
6. Distilled water is aspirated till instrument reads 0.
7. The standard solutions no. 1, 2, 3, test solution, and then standards 4, 5, 6 are aspirated.
The results are recorded.
8. Distilled water is aspirated for at least 5 minutes to clean the system(FLAPHO flame photometer).
(FLAPHO is a dual channel instrument, which measures concentrations of Na simultaneously).







48



TABULATION


Flask No.

Concentration

Absorbance

1


2


3


4


5


6

Unknown Solution
X




















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?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





3


PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)
1. Fundamentals
To provide students with a solid foundation in Mathematics, Science and fundamentals of engineering,
enabling them to apply, to find solutions for engineering problems and use this knowledge to acquire higher
education
2. Core Competence
To train the students in chemistry practicals so that they apply their knowledge and training to compare,
and to analyze various engineering industrial problems to find solutions
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice this enables
them to find solutions for the real time problems in industry, and to design products
4. Professionalism
To inculcate professional and effective communication skills, leadership qualities and team spirit in the
students to make them multi-faceted personalities and develop their ability to relate engineering issues to
broader social context
5. Lifelong Learning/Ethics
To demonstrate and practice ethical and professional responsibilities in the industry and society in the
large, through commitment and lifelong learning needed for successful professional career






4


PROGRAMME OUTCOMES (POs)
To demonstrate and apply knowledge of Mathematics, Science and engineering fundamentals in the following
experiments.
1 .To estimate HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. To determine total, temporary & permanent hardness of water by EDTA method.
3. To determine DO content of water sample by Winkler?s method.
4. To determine chloride content of water sample by Argentometric method.
5. To estimate copper content of the given solution by Iodometry.
6. To determine strength of given hydrochloric acid using pH meter.
7. To determine strength of acids in a mixture of acids using conductivity meter.
8. To determine iron content of the given solution using potentiometer.
9. To estimate iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. To estimate sodium and potassium present in water using flame photometer.
11. To determine molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. To determine Pseudo first order kinetics ? ester hydrolysis.
13. To determine Corrosion experiment ? weight loss method.
14. To estimate CMC.
15. To estimate Phase change in a solid.
16. To determine strength of strong acid vs strong base using conductivity meter.











5

BS8161 - CHEMISTRY LABORATORY
SYLLABUS


? To make the student to acquire practical skills in the determination of water quality
parameters through volumetric and instrumental analysis.

? ???? ??? ???? ?? ???? ? ? ?To acquaint the students with the determination of molecular weight of a polymer by
viscometery.

LIST OF EXPERIMENTS:
1. Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. Determination of total, temporary & permanent hardness of water by EDTA method.
3. Determination of DO content of water sample by Winkler?s method.
4. Determination of chloride content of water sample by Argentometric method.
5. Estimation of copper content of the given solution by Iodometry.
6. Determination of strength of given hydrochloric acid using pH meter.
7. Determination of strength of acids in a mixture of acids using conductivity meter.
8. Estimation of iron content of the given solution using potentiometer.
9. Estimation of iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. Estimation of sodium and potassium present in water using flame photometer.
11. Determination of molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. Pseudo first order kinetics ? ester hydrolysis.
13. Corrosion experiment ? weight loss method.
14. Determination of CMC.
15. Phase change in a solid.
16. Conductometric titration of strong acid vs strong base.




? The students will be outfitted with hands-on knowledge in the quantitative chemical
analysis of water quality related parameters.
COURSE OBJECTIVES
COURSE OUTCOMES
6


INDEX [ SEMESTER ? I ]


S.No.



Date


Experiment

Date of
submission



Mark


Signature

1.

Estimation of HCl using Na 2CO 3 as
primary standard and Determination of
alkalinity in water sample.



2.


Determination of total, temporary &
permanent hardness of water by EDTA
method.



3.


Determination of chloride content of water
sample by argentometric method.



4.


Determination of strength of given
hydrochloric acid using pH meter.



5.


Determination of strength of acids in a
mixture of acids using conductivity meter.



6.


Estimation of iron content of the given
solution using potentiometer.



7.





Conductometric titration of strong acid Vs
strong base.



8.



Estimation of copper content of the given
solution by Iodometry


9.
Estimation of sodium and potassium
present in water using flame photometer




7




CONTENTS


S.No.


NAME OF EXPERIMENT

PAGE
No.
SEMESTER - I
1.
Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in
water sample.
09
2. Determination of total, temporary & permanent hardness of water by EDTA method. 15
3. Determination of chloride content of water sample by Argentometric method. 21
4. Determination of strength of given hydrochloric acid using pH meter. 25
5. Determination of strength of acids in a mixture of acids using conductivity meter. 29
6. Estimation of iron content of the given solution using potentiometer. 33
7. Conductometric titration of strong acid Vs strong base.

39


42

8


Estimation of copper content of the given solution by Iodometry 43
9 Estimation of sodium and potassium present in water using flame photometer 47






8



SHORT PROCEDURE:

CONTENTS
TITRATION
Estimation of alkalinity in water sample
(Std HCl Vs water sample)

Burette solution

Std. HCl


Pipette solution

Water sample


Indicator


(i) Phenolphthalein
(ii) Methyl orange


End point

(i) Disappearance of pink colour
(ii) Appearance of reddish orange colour






Relationship
between P &M
Nature of alkalinity
Amount of individual
alkalinities
OH
-
HCO 3
-


CO 3
2-

P = M

only OH
-

P or M

?
0.0

0.0


2P = M

only CO 3
2-


2P or M


0.0


0.0


?

P =0, M?0

only HCO 3
-



M



0.0



?

0.0


2P > M


OH
-
&CO 3
2-


OH
-
= 2P-M
CO 3
2-
= 2(M-P)


?

0.0

?

P < ? M




HCO 3
-
&CO 3
2-


HCO 3
-
= M-2P
CO 3
2-
= 2P

0.0 ? ?




9





Expt. No. 1 DETERMINATION OF ALKALINITY IN WATER
AIM
To determine the type and amounts of alkalinity in the given water sample. A standard solution of Na 2CO 3
of strength ____N is given.

PRINCIPLE
Alkalinity in water is due to the presence of soluble hydroxides, bicarbonates and carbonates.
Determination of various types and amounts of alkalinity is easily carried out by titration with standard HCl
employing the indicators phenolphthalein and methyl orange independently or in succession.

The following reactions occur when different types of alkalinity are neutralized with acid.

OH
?
+ H
+
? H 2O completed at pH 8.2-9.0 ----- (1)

CO 3
2 ?
+ H
+
? HCO 3
?
----- (2)

HCO 3
?
+ H
+
? (H 2CO 3) ? H 2O + CO 2, completed at pH 4.2-5.5 ----- (3)

Neutralisation (1) & (2) will be notified by phenolphthalein end-point while all the three will be

accounted by
methyl orange end-point. Bicarbonate in eqn. (3) may be due to the existence of soluble free bicarbonate salts and
bicarbonates resulting from half neutralization of soluble carbonates (eqn. (2))

Various steps to be followed

a) A known volume of water sample is titrated against std. HCl using first phenolphthalein indicator till
end-point (P) and the titration is continued without break using methyl orange indicator till the end-
point (M).



10


Titration

Estimation of Alkalinity in water sample

Standard HCl Vs Water sample Indicator: 1. Phenolphthalein
2. Methyl Orange


S.No.
Volume
of water
sample (ml)
Burette Reading
Concordant value

Initial Phenolphthalein End
Point (P)
Methyl Orange End
Point (M)

1

2






CALCULATION

Hydroxide ion alkalinity
Volume of HCl (2P-M) = ???????ml

Strength of HCl = ???????? N

Volume of water sample = ???????...ml

Strength of water sample = Volume of HCl (2P-M) x Strength of HCl
Volume of water sample

=

? Hydroxide ion alkalinity in terms of
CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ??????.mg/l







11




b) From the magnitudes of the P & M, the nature of alkalinity can be arrived as follows:

(i) P = M => Presence of only OH
-

(ii) 2P = M => Presence of only CO 3
2-

(iii) P =0, M=0 => Presence of only HCO 3
-
(iv) 2P > M => Presence of OH
-
& CO 3
2-
(v) 2P < M => Presence of HCO 3
-
& CO 3
2-

(Mixture of OH
-
& HCO3
-
is not listed since they do not exist together and are considered equivalent to CO 3
2-
).

PROCEDURE
TITRATION
ESTIMATION OF ALKALINITY IN WATER SAMPLE

Exactly 20 ml of water sample is pipetted out into a clean conical flask. Few drops of phenolphthalein
indicator are added and titrated against a standardized HCl taken in the burette. The end point is the
disappearance of pink colour, which is noted as P. Few drops of methyl orange indicator is added to the same
solution. The solution turns to yellow. The titration is continued further by adding same HCl without break till the
end point is reached. The end point is the colour change from yellow to reddish orange.

The experiment is repeated to get concordant values. From the magnitudes of P & M values, the type of
alkalinity present in the water sample is inferred and the individual amounts are calculated and reported.










12


Carbonate ion alkalinity

Volume of HCl 2 (M ? P) = ??? ????????ml

Strength of HCl = ??.?????..???...N

Volume of water sample =........................................ml

Strength of water sample = Volume of HCl 2 (M ? P) x Strength of HCl
Volume of water sample

= ???????????.. N




? Carbonate ion alkalinity
in terms of CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ???????????mg/l

















13





RESULT

1) The type of alkalinity present in the water sample = -------------------------ions.

2) The individual amounts of alkalinity present in the water sample:
Hydroxide ion alkalinity

= ----------------- ppm
Carbonate ion alkalinity = ------------------ ppm
Bicarbonate ion alkalinity = ----------------- ppm





VIVA-VOCE


1. What is meant by alkalinity?
2. What are the ions responsible for alkalinity?
3. Why OH
-
and HCO 3
?
ions cannot exist together in water?
4. What are the ions responsible for alkalinity when 2P > M?
5. What is the pH range for both in acidic and basic solutions?
6. What is the colour of phenolphthalein in an acid and in an alkaline solution?
7. What is the purpose of using two indicators in same titration?
8. What are the possible combinations of ions for alkalinity?
9. How is the amount of alkalinity expressed?
10. What are the types of indicator used in this experiment?







14

SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II TITRATION III
Standardisation of
EDTA
(EDTA Vs Std
Hard water)
Determination of
total hardness
(Std EDTA Vs Hard
water sample)
Determination of
permanent hardness
(Std EDTA Vs Boiled
Hard water sample)

Burette solution

EDTA solution

EDTA solution

EDTA solution

Pipette solution

20ml Std. hard water

20 ml hard water sample

20ml boiled hard water sample

Indicator

2 drops of EBT

2 drops of EBT

2 drops of EBT

Additional soln.


Ammoniacal Buffer
solution (5ml)

Ammoniacal Buffer solution
(5ml)

Ammoniacal Buffer solution
(5ml)
End point Wine - red to Steel blue Wine - red to steel blue Wine - red to Steel blue




STANDARDISATION OF EDTA
Titration - I
Std. HARD WATER Vs EDTA Indicator: EBT

S. No.
Volume of std hard
water (ml)
Burette Reading Volume of
EDTA
(V 1) (ml)
Concordant value

Initial

Final



Volume of std .hard water taken = 20 ml
Volume of EDTA consumed (V 1) = --------------- ml
1 ml of std.hard water = 1mg of CaCO 3
20 ml of std hard water = 20 mg of CaCO 3

V 1 ml of EDTA solution containing 20 mg of CaCO 3
1 ml of EDTA solution = 20 / V 1 mg of CaCO 3
= -----------------------mg of CaCO 3


15

Expt. No. 2 DETERMINATION OF TOTAL, TEMPORARY AND
PERMANENT HARDNESS OF WATER

AIM
To estimate the amount of total, temporary & permanent hardness in the given sample of water.

PRINCIPLE
The estimation is based on the complexometric titration.

(i) Total hardness of water is estimated by titrating against EDTA using EBT indicator.
EBT+M ?[EBT-M] (unstable complex)
(EBT-M) (Unstable complex) +EDTA ? [EDTA-M] (stable complex) +EBT
EBT indicator forms wine- red colored complex with metal ions present in water. On addition of EDTA
metal ions preferably forms complexes with EDTA and steel blue EBT indicator is set free. Therefore
change of colour from wine- red to steel blue denotes the end point.

(ii) Temporary hardness is removed by boiling the water.
Ca (HCO 3) 2 ? CaCO 3 +CO 2 ?+H 2O
Mg (HCO 3) 2 ? Mg(OH) 2 +2CO 2 ?
The precipitate is filtered and the remaining permanent hardness is estimated using EDTA.

PROCEDURE

TITRATION ? I
STANDARDISATION OF EDTA

Pipette out 20ml of standard hard water into a 250ml conical flask. Add 5ml of buffer solution and 3
drops of eriochrome black T indictor. Titrate the solution with EDTA from the burette until the colour
changes from wine- red to steel blue at the end point. Repeat the titration for concordant values. Let the
titre value be V 1ml.


16


Titration-II
SAMPLE HARD WATER Vs Std EDTA Indicator: EBT

S.No. Volume of sample
hard water (ml)
Burette Reading Volume of
EDTA
(V 2) (ml)
Concordant value

Initial

Final




CALCULATION

Calculation of total hardness


Volume of EDTA consumed (V 2) = ------------------------- ml
1ml of EDTA = 20 / V 1 mg of CaCO 3
V 2 ml of EDTA = 20 / V 1 x V 2 mg of CaCO 3

( i.e), If 20ml of sample hard water contains 20 x V 2 mg of CaCO 3 / V 1

Then 1000ml of water sample = 20 x V 2 x 1000 / V 1 x 20 mg of CaCO 3

= 1000 x V 2 / V 1 mg of CaCO3

Total hardness of given water sample = ---------------------ppm









17



DETERMINATION OF TOTAL HARDNESS

Pipette out 20ml of sample hard water into a clean conical flask. Add 5ml of buffer solution and 4 -5
drops of Eriochrome black -T indicator. Titrate the wine - red coloured solution with EDTA from the burette until
the colour steel blue appears at the end point. Repeat the titration for concordant values. Let the titre value be
V 2ml.



DETERMINATION OF PERMANENT HARDNESS

Take 100ml of hard water sample in a 500ml beaker and boil gently for about 1hour. Cool, filter it into a
100ml standard flask and make the volume up to the mark. Take 20ml of this solution and proceed it in the same
way as in titration (I). The volume of EDTA consumed corresponds to the permanent hardness of the water
sample. Let the titre value be V 3ml. Temporary hardness is calculated by subtracting permanent hardness from
total hardness.





















18




DETERMINATION OF PERMANENT HARDNESS
BOILED SAMPLE WATER Vs Std. EDTA Indicator: EBT


S.No.
Volume of boiled
hard water (ml)
Burette Reading (ml) Volume of
EDTA
(ml)

Concordant value

Initial Final



CALCULATION OF PERMANENT HARDNESS


Volume of EDTA consumed V 3 = ---------------------ml

1ml of EDTA = 20 / V 1 mg of CaCO 3

V 3ml of EDTA = 20 / V 1 x V 3 mg of CaCO 3

(i.e) 20 ml of boiled sample hard water = 20 / V 1 x V 3 mg of CaCO 3

Then 1000ml of boiled water sample = 20 / V 1 x V 3 / 20 * 1000mg of CaCO 3

= 1000 x V 3 / V 1 mg of CaCO 3

permanent hardness of boiled water sample = -----------------ppm

Temporary hardness of the given water sample = Total hardness ? Permanent hardness

= ------------------ppm

19







RESULT

(i) Total hardness of the given sample water = -------------- ppm.
(ii) Permanent hardness of the given sample water = --------------- ppm.
(iii) Temporary hardness of the given sample water = ----------------ppm.







VIVA-VOCE

1. Define ? Hard water
2. What is the structure of EDTA?
3. How will you calculate temporary hardness?
4. What is the role of the buffer in EDTA titration?
5. What is the permissible limit of hardness in drinking water?
6. Name the hardness producing ions present in water.
7. Name two salts which are responsible for temporary hardness.
8. Why is CaCO 3 taken as the standard?
9. Write the expansion of EDTA.
10. What is meant by EBT?











20





SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II
Standardisation of
AgNO 3
Estimation of Chloride
Burette solution

AgNO 3 solution

Std. AgNO 3 solution

Pipette solution

20ml std KCl solution

20 ml water sample

Indicator

1ml K 2CrO 4

1ml K 2CrO 4


End point

yellow to reddish brown

yellow to reddish brown

Titration I
Std. AgNO3 Vs KCl Indicator: Potassium Chromate













CALCULATION

Volume of KCl (V 1) = ------- ml

Strength of KCl (N 1) = ------- N

Volume of Silver Nitrate (V 2) = -------- ml

Strength of Siver Nitrate V 1N 1
N 2 =
V 1

= --------------------- N

S.No.
Volume of KCl
(ml)
Burette Reading (ml)
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

21




Expt.No. 3 ESTIMATION OF CHLORIDE CONTENT IN WATER
(ARGENTOMETRIC METHOD)
AIM
To estimate the amount of chloride present in given water sample by Argentometric method (Mohr?s
method). You are provided with standard solution of NaCl of strength --------N and a approximately N/10 solution of
Silver nitrate.

PRINCIPLE
The Chloride ion in the form of NaCl, KCl, CaCl 2, MgCl 2 etc., present in the water sample can be estimated
by Argentometric method or known as Mohr?s method. It is an example for precipitation titration. The reaction
between std. Sodium chloride and Silver nitrate is given below.
AgNO 3 + NaCl ? AgCl ? + NaNO 3
The completion of reaction can be observed by employing potassium chromate as the indicator. The end
point is the colour change from yellow to reddish brown due to the following reaction.
2AgNO 3 + K 2CrO 4 ? Ag 2CrO 4 ? + 2KNO 3
Potassium chromate indicator will not be precipitated as silver chromate until all the chlorides in the solution
have been precipitated as AgCl Since a precipitation reaction takes place in preference, this reaction takes place
only at the end point.

PROCEDURE
TITRATION I: STANDARDISATION OF SILVER NITRATE
Pipette out 20ml of standard sodium or potassium chloride solution into a clean conical flask. Add 1ml of 5%
K 2CrO 4 indicator, as the solution turns yellow in colour. Titrate it against silver nitrate solution taken in the burette.
Observe the nearness of the end point through the formation of coagulated silver chloride precipitate at the bottom
of the flask. Now add the silver nitrate drop by drop until the solution gets a faint reddish brown tinge. Repeat the
titration for concordant value. Let the volume of silver nitrate be V 2ml.





22






TITRATION - II

Std AgNO3 Vs WATER SAMPLE Indicator: Potassium Chromate













CALCULATION

Volume of Silver Nitrate (V 3) = ------------ ml

Strength of Siver Nitrate (N 3) = ------------- N

Volume of Water sample (V 4) = -------------- ml

Strength of Water sample V 3 N 3
(N 4) =
V 4

= ----------------- N

Amount of Chloride ion present in 1000 ml of the water sample = Equivalent mass of HCl X 1000


= N 4 x 35.46 x 1000


= -----------------mg/l







S.No.
Volume of water
sample (ml)
Burette Reading
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

23





TITRATION - II
ESTIMATION OF CHLORIDE ION

Pipette out 40 ml of the given water sample into a clean conical flask.To this sample add 1ml of 5% K 2CrO 4
indicator and titrate it against the standardized silver nitrate solution taken in the burette and continue the titration
until the solution produces a reddish brown colour. Note down the end point and repeat the titration for
concordance. Let the volume be V 3ml.







RESULT

The amount of chloride ion present in the water sample = ----------------- mg/l.




VIVA-VOCE

1. Why is this method known as Argentometric method?
2.
What is the chemical reaction between AgNO 3 and Cl
-
ions present in water?

3.
What is the form of Chloride ion present in water?

4. What is the reaction between AgNO 3 and K 2CrO 4 ?
5. What is the name of the method used in this titration?
6. Name the link solution used in the determination.
7. Name the solution used to standardize AgNO 3.
8. What is the indicator used in the determination?
9. How will you calculate the amount of chloride ion in the given solution?
10. What is the colour change in the titration?




24




SHORT PROCEDURE


CONTENTS

TITRATION I

TITRATION II
Burette solution

Std Sodium Hydroxide

Std Sodium Hydroxide

Pipette solution

20 ml hydrochloric acid 20 ml hydrochloric acid
Additional solution


20 ml distilled water

20 ml distilled water


End point



Sudden increase in pH
pH gradual increase

Equivalent Weight of HCl = 36.5







ROUGH GRAPH FAIR GRAPH











pH
? pH/ ? V





Volume of NaOH
(ml)
Volume of NaOH
(ml)





25



Expt. No. 4 DETERMINATION OF STRENGTH OF HCl by pH METRY

AIM
To determine the strength of given HCl by pH metry. A standard solution of 0.1N NaOH is provided.

PRINCIPLE
The pH of a solution is related to H
+
ion concentration by the following formula.

. pH = -log [ H
+
]

pH of a solution is indirectly related to H
+
ion concentration. When NaOH is added slowly to HCl, H
+
ions
get neutralized by OH
-
ions. The pH increases slowly.

H
+
+ Cl
-
+ Na
+
+ OH
-
? Na
+
+ Cl
-
+H 2O

When all H
+
ions of HCl are neutralized at the end point, addition of NaOH causes high increase in pH
because of the addition of excess OH
-
ions.

MATERIALS REQUIRED
pH meter, Glass electrode, Burette, Pipette, Std.NaOH, approximately N/10 HCl .

PROCEDURE

The burette is washed with distilled water, rinsed with the given std. Sodium hydroxide and filled with the
same solution. Exactly 10ml of the given HCl solution is pipetted out into a clean beaker. It is then diluted to 50ml
with distilled water. A glass electrode is dipped into the solution and its terminals are connected to a pH meter.

26

TITRATION - I
S.No Volume of
NaOH (ml)
pH
1

2

3

4

5

6

7

8

9

10


TITRATION - II



CALCULATION

Volume of NaOH (V 1) = ------------------- ml ( titre value)
Strength of NaOH (N 1) = ------------------- N
Volume of HCl (V 2) = ------------------ml
Strength of HCl (N 2) = ------------------ N
N 2 = V 1 N 1 / V 2
Strength of HCl = -------------------- N
Amount of HCl present in 1000ml of the given solution = Strength x equivalent weight of HCl
= ------------------ X 36.5
= --------------------- g
S.No Volume of
NaOH (ml)
pH
11

12

13

14

15

16

17

18

19

20

S.No
Volume of
NaOH (ml)
pH ?pH ?V ?pH / ?V
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
27



Now NaOH is gradually added from the burette to HCl taken in the beaker. pH of the solution is noted for
each addition of NaOH. This process is continued until 5 readings are taken after the end point.
A fair titration is performed to find the exact end point.





RESULT

(i) Strength of the given HCl solution = ---------------- N
(ii) Amount of HCl present in a litre of the solution = ---------------- g


VIVA-VOCE

1. What is meant by pH?
2. What is the name of the reference electrode used ?
3. Why does pH value increase suddenly at the end point?
4. What is the indicator used in the titration?
5. What is the pH range of human blood?
6. What is the unit of pH?
7. How will you calculate the amount of HCl?
8. How is glass electrode represented?
9. Why is glass electrode known as ion selective electrode?
10. What is the chemical reaction involved in this titration?





28




SHORT PROCEDURE


CONTENTS
TITRATION
Burette solution

Std Sodium Hydroxide

Pipette solution

20 ml mixture of acid (HCl+ CH 3COOH)


Additional solution

20 ml distilled water


End point

Conductivity decreases-slowly increases-Sudden increase



Equivalent Weight of HCl = 36.5


Equivalent Weight of CH 3COOH = 60



MODEL GRAPH


Conductance
Volume of NaOH
Mixture of Acids






29




Expt. No. 5 CONDUCTOMETRIC TITRATION OF MIXTURE
OF ACIDS

AIM
To determine the amount of a strong acid and a weak acid present in the given solution.

PRINCIPLE

Solution of electrolytes conducts electricity due to the presence of ions. Since specific conductance of a
solution is proportional to the concentration of ions in it, conductance of the solution is measured during the titration.

HCl + NaOH ? NaCl + H 2O (I neutralization)

CH 3COOH + NaOH ? CH 3COONa + H 2O (II neutralization)

When a solution of HCl is treated with NaOH the fast moving hydrogen ions are progressively replaced by
slow moving sodium ions. As a result conductance of the solution decreases. This decrease will take place until the
first neutralisation point is reached. Further addition of alkali results in formation of sodium acetate.

Since sodium acetate is stronger than acetic acid conductivity slowly increases until all acetic acid is
completely neutralized.(II Neutralisation) This is due to the presence of fast moving OH
-
ions. Anymore addition of
alkali increases the conductance sharply.

PROCEDURE
The burette is filled with NaOH solution upto zero mark. The given unknown solution (mixture of a weak &
a strong acid) is transferred into a 100ml standard flask and made upto the mark with distilled water. 20ml of the
made up solution is pipetted out into a clean 100ml beaker. The solution is diluted to 20ml using distilled water. A
conductivity cell is dipped into the solution and the terminals are connected to a conductivity meter.
30


TITRATION


CALCULATION OF STRENGTH OF HCl
Volume of NaOH (V 1) = --------------- ml (titre value)
Strength of NaOH (N 1) = ---------------- N
Volume of HCl (V 2) = ------------ ml
Strength of HCl (N 2) = -------------- N

N 2 = V 1 N 1 / V 2
Strength of HCl = ---------------- N
CALCULATION OF STRENGTH OF CH3COOH
Volume of NaOH (V 1) = ------------ ml (titre value)
Strength of NaOH (N 1) = ------------ N
Volume of CH 3COOH (V 2) = ------------ ml
Strength of CH 3COOH (N 2) = ------------ N
N 2 = V 1 N 1 / V 2

Strength of CH 3COOH = ------------ N



S.No

Volume of NaOH
(ml)

Conductance (mho)

14

15

16

17
18
19
20

21
22
23
24
25
26

S.No

Volume of NaOH
(ml)

Conductance (mho)

1
2
3
4
5
6
7
8
9
10
11
12
13
31

The burette solution is added to the unknown solution in the beaker in 0.5 ml increments, the solution is
stirred using a glass rod, and the observed conductance values are read from the meter. The conductance values
show decrease in the initial values, then gradually increases and finally shows a steep increase. The titration hence
shows two end-points (i.e) I neutralization (weak acid) & II neutralization (strong acid).
The accurate end-point is obtained by plotting a graph between observed conductance Vs volume of
NaOH added.

RESULT
The strength of acids present in the given unknown solution are:
a) Strong acid = ---------------- N
b) Weak acid = -----------------N



VIVA-VOCE

1. What is weak acid?
2. How many end points are obtained from the graph? Comment two end points.
3. Why is the conductance increase in the first end point?
4. What mixture of acids used in this titration?
5. Write the neutralization reaction between CH 3COOH and NaOH.
6. What is the solution present in the conductivity cell?
7. What are strong and weak electrolytes?
8. Give an example for strong acid and weak acid.
9. What is the strong electrolyte of weak electrolyte?
10. Give an example for strong base.









32

SHORT PROCEDURE



















ROUGH GRAPH







EMF(mV)






Volume of Potassium dichromate (ml)

FAIR GRAPH









? E / ? V

Volume of Potassium dichromate (ml)




CONTENTS

TITRATION I

TITRATION II
Burette solution

Std Potassium dichromate

Std Potassium dichromate

Pipette solution

10 ml of FAS


10 ml of FAS



Additional
solution

20 ml distilled water+
10 ml of dil H 2SO 4


20 ml distilled water+
10 ml of dil H 2SO 4

End point

Sudden increase in EMF

EMF increases and decreases

Equivalent Weight of Ferrous ion = 55.85

33


Expt. No. 6 ESTIMATION OF FERROUS ION BY POTENTIOMETRIC
TITRATION

AIM
To estimate the amount of ferrous ion present in whole of the given solution potentiometrically. A standard
solution of potassium dichromate of strength -----------N is provided.

PRINCIPLE

Potentiometric titrations depend on measurement of emf between reference electrode and an indicator
electrode. When a solution of ferrous iron is titrated with a solution of potassium dichromate, the following redox
reaction takes place.

6Fe
2+
+ Cr 2O 7
2-
+ 14 H
+
? 6Fe
3+
+ 2Cr
3+
+ 7H 2O

During this titration Fe
2+
is converted in to Fe
3+
, whose concentration increases. At the end point, there
will be a sharp change due to sudden removal of all Fe
2+
ions.
The cell is set up by connecting this redox electrode with a calomel electrode as shown below:

Pt, Fe
2+
, Fe
3+
, II KCl , HgCl 2 (s), Hg

A graph between EMF measured against the volume of potassium dichromate added is drawn and the
end point is noted from the graph.

PROCEDURE

10ml of Ferrous solution is pipetted out into a 100 ml beaker. 10ml of dil.H 2SO 4 and 20ml of distilled water
are added. A platinum electrode and a calomel electrode are dipped into this solution and connected to the
potentiometer. Then 1ml of potassium dichromate is added to the solution and stirred well for 30 seconds. The
EMF is measured and the titration is continued by adding potassium dichromate in 1ml increments till five
measurements after the end point.



34


ROUGH TITRATION



S.No.

Volume of dichromate (ml)

EMF (mV)


1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.





35







A graph is drawn by plotting the emf against the volume of potassium dichromate and the end point range is
fixed.


About 20ml of Ferrous solution is pipetted out and the titration is continued by adding 0.1ml increaments of
potassium dichromate in the end point range. The emf is measured for each 0.1ml after stirring the solution well.


A graph is plotted between emf and the volume of potassium dichromate and also a first derivative graph is
plotted ( ? E/ ? V against vol. of K 2Cr 2O 7). The strength of Ferrous solution and the amount of Ferrous ion present are
calculated from the end point.



























36

FAIR TITRATION

S.No Volume of
Dichromate (ml)
Emf (mV) ?E ?V ?E/?V






















CALCULATION

Volume of Potassim dichromate (V 1) = -------------- ml
Normality of Potassium dichromate (N 1) = --------------- N
Volume of Ferrous sulphate (V 2) = --------------- ml
Normality of Ferrous sulphate (N 2) = --------------- N
Amount of Ferrous ion present in 1000ml of the solution = Normality X Equivalent weight of ferrous ion
= --------------- X 55.85 g

The amount of Ferrous ion present in the given solution = ----------------- g






37









RESULT

The amount of Ferrous ion present in the whole of the given solution = --------------- g.








VIVA-VOCE

1. What is EMF?
2. What is the basic principle of potentiometric titration?
3. Why does EMF increase during the titration?
4. Write the cell representation of the titration.
5. What is redox reaction?
6. What is the purpose of adding sulphuric acid?
7. What are the advantages of potentiometric titration?
8. How will you obtain the end point in the titration?
9. What is the name of the indicator electrode used in this titration?
10. What is the name of the reference electrode used?








38



SHORT PROCEDURE



CONTENTS

TITRATION
Burette solution

Sodium Hydroxide

Pipette solution

20 ml HCl


Additional solution

20 ml distilled water


End point

Decrease in conductance- increase in conductance

Equivalent Weight of HCl = 36.5
















Conductance

Volume of NaOH ( ml)









39


Expt.No. 7 CONDUCTOMETRIC TITRATION OF STRONG ACID
WITH STRONG BASE
AIM

To determine the strength of a strong acid by titrating a strong acid and strong base conductometrically. A
standard solution of NaOH of known strength ---------N is provided.

PRINCIPLE
Solution of electrolytes conducts electricity due to the presence of ions. The specific conductance of a
solution is proportional to the concentration of ions in it. The reaction between HCl and NaOH may be represented
as,
HCl +NaOH ? NaCl + H 2O

When a solution of hydrochloric acid is titrated with NaOH, the fast moving hydrogen ions are
progressively replaced by slow moving sodium ions. As a result conductance of the solution decreases, this
decrease in conductance will take place until the end point is reached. Further addition of alkali raises the
conductance sharply, as there is an excess of hydroxide ions.

A graph is drawn between volume of NaOH added and the conductance of solution. The exact end point
is intersection of the two lines.

PROCEDURE

The given HCl is made up in a 100ml standard flask. 10 ml of this solution is pipetted out in a beaker. The
burette is filled with standard sodium hydroxide upto the mark.

A conductivity cell is dipped into the beaker with HCl solution and connected to the terminals of the
conductivity bridge. About 1ml of STD NaOH is added and stirred well for 30 seconds. The conductance is
measured and the titration is continued till five measurements after the endpoint. A graph is plotted for the
conductance values against the volume of NaOH and the endpoint range is fixed.

40


TABLE



CALCULATION
Volume of Sodium Hydroxide (V 1) = ------------- ml
Normality of Sodium Hydroxide (N 1) = ------------- N
Volume of Strong acid (V 2) = ------------- ml
Normality of Strong acid (N 2) = V 1 N 1
V 2

The strength of the given strong acid = ------------- N




S.NO
Volume of NaOH
(ml)
Conductance
(mho)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
41

The above titration is repeated again and the exact endpoint is found out by adding in increments of 0.1ml
of NaOH in the end point range and continued after endpoint upto five readings.
A graph is plotted with the conductance values against the volume of NaOH and then the strength of the
strong acid is found out.


RESULT

The strength of the given strong acid is found to be = --------------- N







VIVA-VOCE

1. What is the basic principle of conductometric titration?
2. Why is conductance decreased and increased during the titration?
3. What is conductance mention its unit?
4. Give some examples for Strong acids and Strong bases.
5. Write the reaction between HCl and NaOH.
6. What is meant by strong base?
7. Explain why HCl is a strong acid?
8. Explain why the strength of burette solution is always greater than the pipette solution in conductometric
titration.
9. What is the equivalent weight of HCl and NaOH?
10. Write the formula that is used to calculate the amount of HCl.











42

ESTIMATION OF COPPER

Alloy solution Vs Std. Na2S2O3 (Thio) Indicator: Starch

S.No.
Volume of
Alloy Solution
(ml)
Burette Reading (ml) Volume of
Thio
(ml)
Concordant value
(ml)
Initial Final

1.

2.

3.












CALCULATION
Volume of Na 2S 2O 3 V 1 = ------------- ml

Strength of Na 2S 2O 3 N 1 = ------------- N

Volume of brass solution V 2 = ------------- ml

Strength of brass solution N 2 = ------------- ?

= V 1 x N I / /V 2

= -------------

Strength of copper solution is = ------------- N



















43


Expt.No.8 ESTIMATION OF COPPER IN BRASS
AIM
To estimate the amount of copper present in the given sample of brass.

PRINCIPLE
Brass is an alloy with 55% copper and 33% zinc and small amount of lead and aluminum. Brass is dissolved
in conc. nitric acid to convert copper present in the alloy to cupric ions. Then copper is estimated iodometrically by
titrating the iodine that was liberated against standard sodium thio sulphate solution using starch as indicator.

2 Cu
2+
+ 4I
-
? 2 CuI + I2
I 2 + 2 Na 2S 2O 3 ? Na 2S 4O 6 + 2NaI

CHEMICALS REQUIRED
0.1N Potassium dichromate, 0.1N sodium thio sulphate, 0.01M EDTA, Con. HNO 3 , , KI, EBT,
NH 3OH / NH 4Cl buffer, Starch.

PROCEDURE
PREPARATION OF BRASS ALLOY SOLUTION

About 0.2g of the sample of brass was weighed accurately and transferred into a clean dry 250ml beaker. To
this about 10ml of con. Nitric acid was added and allowed to boil for a small interval of time till the alloy was dissolved.
This was cooled, diluted with water and made upto 250 ml in a standard flask.

TITRATION I
STANDARDIZATION OF Na2S2O3 WITH K2Cr2O7 SOLUTION
20ml of the standard potassium dichromate solution is pipetted out into a conical flask. 20ml of dil.sulphuric
acid and 10ml of 10% KI are added. The liberated iodine is titrated against sodium thio sulphate taken in the burette till
the colour changes to yellowish green. 1ml of starch is added till the colour changes from blue to light green colour.
Titration is repeated for concordance.
44



CALCULATION


Amount of copper in 1lt of given brass solution = Strength of solution x Eq. Wt of Cu


= ------------------ N x 63.5

= -------------------------

So, Amount of copper in 100ml of given brass solution = ------------------- N x 63.5 x 100 / 1000



ie, ------------g of brass contains = -------------------- g of copper


therefore, % of copper in the given brass sample = ------------------- g x 100


= ------------------ g of brass


= ------------------------ %























45


TITRATION II

ESTIMATION OF COPPER

The brass solution is transferred into the 100ml standard flask and 10ml of dil. sulphuric acid is added and
made up to the mark using distilled water.

20ml of the alloy solutionis pipetted out into a conical flask. To this aqueous ammonia is added in drops till
a blue precipitate of Cu(OH) 2 is formed. One or two drops of acetic acid is added to dissolve the precipitate. To
this 10ml of 10% KI is added and titrated against standard thio sulphate using starch as indicator. The end point is
the disappearance of blue colour and appearance of green colour.



RESULT

The given sample of brass was found to contain copper = ------------- %





VIVA-VOCE



1. What is the composition of brass?
2. What is meant by iodometry?
3. What is the principle used in t his method?
4. What is the role of K 2Cr 2O 7?
5. What is the colour change in this titration?
6. Write the chemical reactions involved in this experiments?
7. How will you find out % of copper in brass?
8. What is the role of indicator?
9. What is the equivalent weight of copper?
10. What is the role of adding aqueous ammonia?


46


SHORT PROCEDURE
Standard solutions are prepared by the dilution of the given stock solution. The flasks are numbered and
the solutions are prepared according to the following table using different glass pipettes.



Flask number

1 2 3 4 5 6
Vol. of pipette to use 1 1 2 10 10 10
Vol. of Na stock solution to pipette 0.5 1 2 4 6 8
Conc. of solution obtained (?g/ml) 5 10 10 40 60 80



MODEL GRAPH








ABSORBANCE






CONCENTRATION








47

Expt. No 9 ESTIMATION OF SODIUM BY USING
FLAME PHOTOMETER
AIM
To estimate the amount of sodium present in whole of the given solution.

APPARATUS REQUIRED
1. Flame photometer FLAPHO or Eppendorf.
2. Stock solutions of Na+ and K+, C = 1 mg/ml.
3. 6 numbered 100 ml volumetric flasks.
4. Glass pipettes: 1, 2, 10 ml.

MEASUREMENT PROCEDURE

1. The flame photo meter is switched on.
2. The instrument is kept for warming.
3. Distilled water is fed into the instrument.
4. The element Na is selected by turning the selector ?Elementwahl?.
5. The outer knob ?Messbereich? is turned into position ?100?. The ?Kompensaton I? knob is pulled slightly
out and adjusted to 0. The ?Kompensation I? knob is pressed back. 0 reading is adjusted with
?Kompensation II? if necessary.
6. The most concentrated standard solution (solution number 6) is aspirated and is adjusted to 350 (on
uppermost scale) using inner ?Messbereich? knob.
6. Distilled water is aspirated till instrument reads 0.
7. The standard solutions no. 1, 2, 3, test solution, and then standards 4, 5, 6 are aspirated.
The results are recorded.
8. Distilled water is aspirated for at least 5 minutes to clean the system(FLAPHO flame photometer).
(FLAPHO is a dual channel instrument, which measures concentrations of Na simultaneously).







48



TABULATION


Flask No.

Concentration

Absorbance

1


2


3


4


5


6

Unknown Solution
X




















49




CALCULATION

1. The calibration curves are drawn for sodium and potassium on a sheet of millimeter-
paper. The concentrations are used as abscissa and instrument readouts as ordinate
values.
2. The concentration of sodium and potassium ions in test solution are found from
calibration curves.

RESULT

The amount of sodium present in whole of the given solution = ------------- g


VIVA - VOCE

1. What is meant by flame photometry?
2. How will you prepare blank solution?
3. Define ? Absorbance
4. State Beer ? Lamberts law.
5. What is the absorbance of sodium?
6. How will you find out unknown concentration of solution?
7. What is meant by wavelength?
8. How will you calibrate the instrument?
9. What is meant by flame emission spectroscopy?
10. Distinguish between absorption and emission spectrum.






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?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





3


PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)
1. Fundamentals
To provide students with a solid foundation in Mathematics, Science and fundamentals of engineering,
enabling them to apply, to find solutions for engineering problems and use this knowledge to acquire higher
education
2. Core Competence
To train the students in chemistry practicals so that they apply their knowledge and training to compare,
and to analyze various engineering industrial problems to find solutions
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice this enables
them to find solutions for the real time problems in industry, and to design products
4. Professionalism
To inculcate professional and effective communication skills, leadership qualities and team spirit in the
students to make them multi-faceted personalities and develop their ability to relate engineering issues to
broader social context
5. Lifelong Learning/Ethics
To demonstrate and practice ethical and professional responsibilities in the industry and society in the
large, through commitment and lifelong learning needed for successful professional career






4


PROGRAMME OUTCOMES (POs)
To demonstrate and apply knowledge of Mathematics, Science and engineering fundamentals in the following
experiments.
1 .To estimate HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. To determine total, temporary & permanent hardness of water by EDTA method.
3. To determine DO content of water sample by Winkler?s method.
4. To determine chloride content of water sample by Argentometric method.
5. To estimate copper content of the given solution by Iodometry.
6. To determine strength of given hydrochloric acid using pH meter.
7. To determine strength of acids in a mixture of acids using conductivity meter.
8. To determine iron content of the given solution using potentiometer.
9. To estimate iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. To estimate sodium and potassium present in water using flame photometer.
11. To determine molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. To determine Pseudo first order kinetics ? ester hydrolysis.
13. To determine Corrosion experiment ? weight loss method.
14. To estimate CMC.
15. To estimate Phase change in a solid.
16. To determine strength of strong acid vs strong base using conductivity meter.











5

BS8161 - CHEMISTRY LABORATORY
SYLLABUS


? To make the student to acquire practical skills in the determination of water quality
parameters through volumetric and instrumental analysis.

? ???? ??? ???? ?? ???? ? ? ?To acquaint the students with the determination of molecular weight of a polymer by
viscometery.

LIST OF EXPERIMENTS:
1. Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. Determination of total, temporary & permanent hardness of water by EDTA method.
3. Determination of DO content of water sample by Winkler?s method.
4. Determination of chloride content of water sample by Argentometric method.
5. Estimation of copper content of the given solution by Iodometry.
6. Determination of strength of given hydrochloric acid using pH meter.
7. Determination of strength of acids in a mixture of acids using conductivity meter.
8. Estimation of iron content of the given solution using potentiometer.
9. Estimation of iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. Estimation of sodium and potassium present in water using flame photometer.
11. Determination of molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. Pseudo first order kinetics ? ester hydrolysis.
13. Corrosion experiment ? weight loss method.
14. Determination of CMC.
15. Phase change in a solid.
16. Conductometric titration of strong acid vs strong base.




? The students will be outfitted with hands-on knowledge in the quantitative chemical
analysis of water quality related parameters.
COURSE OBJECTIVES
COURSE OUTCOMES
6


INDEX [ SEMESTER ? I ]


S.No.



Date


Experiment

Date of
submission



Mark


Signature

1.

Estimation of HCl using Na 2CO 3 as
primary standard and Determination of
alkalinity in water sample.



2.


Determination of total, temporary &
permanent hardness of water by EDTA
method.



3.


Determination of chloride content of water
sample by argentometric method.



4.


Determination of strength of given
hydrochloric acid using pH meter.



5.


Determination of strength of acids in a
mixture of acids using conductivity meter.



6.


Estimation of iron content of the given
solution using potentiometer.



7.





Conductometric titration of strong acid Vs
strong base.



8.



Estimation of copper content of the given
solution by Iodometry


9.
Estimation of sodium and potassium
present in water using flame photometer




7




CONTENTS


S.No.


NAME OF EXPERIMENT

PAGE
No.
SEMESTER - I
1.
Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in
water sample.
09
2. Determination of total, temporary & permanent hardness of water by EDTA method. 15
3. Determination of chloride content of water sample by Argentometric method. 21
4. Determination of strength of given hydrochloric acid using pH meter. 25
5. Determination of strength of acids in a mixture of acids using conductivity meter. 29
6. Estimation of iron content of the given solution using potentiometer. 33
7. Conductometric titration of strong acid Vs strong base.

39


42

8


Estimation of copper content of the given solution by Iodometry 43
9 Estimation of sodium and potassium present in water using flame photometer 47






8



SHORT PROCEDURE:

CONTENTS
TITRATION
Estimation of alkalinity in water sample
(Std HCl Vs water sample)

Burette solution

Std. HCl


Pipette solution

Water sample


Indicator


(i) Phenolphthalein
(ii) Methyl orange


End point

(i) Disappearance of pink colour
(ii) Appearance of reddish orange colour






Relationship
between P &M
Nature of alkalinity
Amount of individual
alkalinities
OH
-
HCO 3
-


CO 3
2-

P = M

only OH
-

P or M

?
0.0

0.0


2P = M

only CO 3
2-


2P or M


0.0


0.0


?

P =0, M?0

only HCO 3
-



M



0.0



?

0.0


2P > M


OH
-
&CO 3
2-


OH
-
= 2P-M
CO 3
2-
= 2(M-P)


?

0.0

?

P < ? M




HCO 3
-
&CO 3
2-


HCO 3
-
= M-2P
CO 3
2-
= 2P

0.0 ? ?




9





Expt. No. 1 DETERMINATION OF ALKALINITY IN WATER
AIM
To determine the type and amounts of alkalinity in the given water sample. A standard solution of Na 2CO 3
of strength ____N is given.

PRINCIPLE
Alkalinity in water is due to the presence of soluble hydroxides, bicarbonates and carbonates.
Determination of various types and amounts of alkalinity is easily carried out by titration with standard HCl
employing the indicators phenolphthalein and methyl orange independently or in succession.

The following reactions occur when different types of alkalinity are neutralized with acid.

OH
?
+ H
+
? H 2O completed at pH 8.2-9.0 ----- (1)

CO 3
2 ?
+ H
+
? HCO 3
?
----- (2)

HCO 3
?
+ H
+
? (H 2CO 3) ? H 2O + CO 2, completed at pH 4.2-5.5 ----- (3)

Neutralisation (1) & (2) will be notified by phenolphthalein end-point while all the three will be

accounted by
methyl orange end-point. Bicarbonate in eqn. (3) may be due to the existence of soluble free bicarbonate salts and
bicarbonates resulting from half neutralization of soluble carbonates (eqn. (2))

Various steps to be followed

a) A known volume of water sample is titrated against std. HCl using first phenolphthalein indicator till
end-point (P) and the titration is continued without break using methyl orange indicator till the end-
point (M).



10


Titration

Estimation of Alkalinity in water sample

Standard HCl Vs Water sample Indicator: 1. Phenolphthalein
2. Methyl Orange


S.No.
Volume
of water
sample (ml)
Burette Reading
Concordant value

Initial Phenolphthalein End
Point (P)
Methyl Orange End
Point (M)

1

2






CALCULATION

Hydroxide ion alkalinity
Volume of HCl (2P-M) = ???????ml

Strength of HCl = ???????? N

Volume of water sample = ???????...ml

Strength of water sample = Volume of HCl (2P-M) x Strength of HCl
Volume of water sample

=

? Hydroxide ion alkalinity in terms of
CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ??????.mg/l







11




b) From the magnitudes of the P & M, the nature of alkalinity can be arrived as follows:

(i) P = M => Presence of only OH
-

(ii) 2P = M => Presence of only CO 3
2-

(iii) P =0, M=0 => Presence of only HCO 3
-
(iv) 2P > M => Presence of OH
-
& CO 3
2-
(v) 2P < M => Presence of HCO 3
-
& CO 3
2-

(Mixture of OH
-
& HCO3
-
is not listed since they do not exist together and are considered equivalent to CO 3
2-
).

PROCEDURE
TITRATION
ESTIMATION OF ALKALINITY IN WATER SAMPLE

Exactly 20 ml of water sample is pipetted out into a clean conical flask. Few drops of phenolphthalein
indicator are added and titrated against a standardized HCl taken in the burette. The end point is the
disappearance of pink colour, which is noted as P. Few drops of methyl orange indicator is added to the same
solution. The solution turns to yellow. The titration is continued further by adding same HCl without break till the
end point is reached. The end point is the colour change from yellow to reddish orange.

The experiment is repeated to get concordant values. From the magnitudes of P & M values, the type of
alkalinity present in the water sample is inferred and the individual amounts are calculated and reported.










12


Carbonate ion alkalinity

Volume of HCl 2 (M ? P) = ??? ????????ml

Strength of HCl = ??.?????..???...N

Volume of water sample =........................................ml

Strength of water sample = Volume of HCl 2 (M ? P) x Strength of HCl
Volume of water sample

= ???????????.. N




? Carbonate ion alkalinity
in terms of CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ???????????mg/l

















13





RESULT

1) The type of alkalinity present in the water sample = -------------------------ions.

2) The individual amounts of alkalinity present in the water sample:
Hydroxide ion alkalinity

= ----------------- ppm
Carbonate ion alkalinity = ------------------ ppm
Bicarbonate ion alkalinity = ----------------- ppm





VIVA-VOCE


1. What is meant by alkalinity?
2. What are the ions responsible for alkalinity?
3. Why OH
-
and HCO 3
?
ions cannot exist together in water?
4. What are the ions responsible for alkalinity when 2P > M?
5. What is the pH range for both in acidic and basic solutions?
6. What is the colour of phenolphthalein in an acid and in an alkaline solution?
7. What is the purpose of using two indicators in same titration?
8. What are the possible combinations of ions for alkalinity?
9. How is the amount of alkalinity expressed?
10. What are the types of indicator used in this experiment?







14

SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II TITRATION III
Standardisation of
EDTA
(EDTA Vs Std
Hard water)
Determination of
total hardness
(Std EDTA Vs Hard
water sample)
Determination of
permanent hardness
(Std EDTA Vs Boiled
Hard water sample)

Burette solution

EDTA solution

EDTA solution

EDTA solution

Pipette solution

20ml Std. hard water

20 ml hard water sample

20ml boiled hard water sample

Indicator

2 drops of EBT

2 drops of EBT

2 drops of EBT

Additional soln.


Ammoniacal Buffer
solution (5ml)

Ammoniacal Buffer solution
(5ml)

Ammoniacal Buffer solution
(5ml)
End point Wine - red to Steel blue Wine - red to steel blue Wine - red to Steel blue




STANDARDISATION OF EDTA
Titration - I
Std. HARD WATER Vs EDTA Indicator: EBT

S. No.
Volume of std hard
water (ml)
Burette Reading Volume of
EDTA
(V 1) (ml)
Concordant value

Initial

Final



Volume of std .hard water taken = 20 ml
Volume of EDTA consumed (V 1) = --------------- ml
1 ml of std.hard water = 1mg of CaCO 3
20 ml of std hard water = 20 mg of CaCO 3

V 1 ml of EDTA solution containing 20 mg of CaCO 3
1 ml of EDTA solution = 20 / V 1 mg of CaCO 3
= -----------------------mg of CaCO 3


15

Expt. No. 2 DETERMINATION OF TOTAL, TEMPORARY AND
PERMANENT HARDNESS OF WATER

AIM
To estimate the amount of total, temporary & permanent hardness in the given sample of water.

PRINCIPLE
The estimation is based on the complexometric titration.

(i) Total hardness of water is estimated by titrating against EDTA using EBT indicator.
EBT+M ?[EBT-M] (unstable complex)
(EBT-M) (Unstable complex) +EDTA ? [EDTA-M] (stable complex) +EBT
EBT indicator forms wine- red colored complex with metal ions present in water. On addition of EDTA
metal ions preferably forms complexes with EDTA and steel blue EBT indicator is set free. Therefore
change of colour from wine- red to steel blue denotes the end point.

(ii) Temporary hardness is removed by boiling the water.
Ca (HCO 3) 2 ? CaCO 3 +CO 2 ?+H 2O
Mg (HCO 3) 2 ? Mg(OH) 2 +2CO 2 ?
The precipitate is filtered and the remaining permanent hardness is estimated using EDTA.

PROCEDURE

TITRATION ? I
STANDARDISATION OF EDTA

Pipette out 20ml of standard hard water into a 250ml conical flask. Add 5ml of buffer solution and 3
drops of eriochrome black T indictor. Titrate the solution with EDTA from the burette until the colour
changes from wine- red to steel blue at the end point. Repeat the titration for concordant values. Let the
titre value be V 1ml.


16


Titration-II
SAMPLE HARD WATER Vs Std EDTA Indicator: EBT

S.No. Volume of sample
hard water (ml)
Burette Reading Volume of
EDTA
(V 2) (ml)
Concordant value

Initial

Final




CALCULATION

Calculation of total hardness


Volume of EDTA consumed (V 2) = ------------------------- ml
1ml of EDTA = 20 / V 1 mg of CaCO 3
V 2 ml of EDTA = 20 / V 1 x V 2 mg of CaCO 3

( i.e), If 20ml of sample hard water contains 20 x V 2 mg of CaCO 3 / V 1

Then 1000ml of water sample = 20 x V 2 x 1000 / V 1 x 20 mg of CaCO 3

= 1000 x V 2 / V 1 mg of CaCO3

Total hardness of given water sample = ---------------------ppm









17



DETERMINATION OF TOTAL HARDNESS

Pipette out 20ml of sample hard water into a clean conical flask. Add 5ml of buffer solution and 4 -5
drops of Eriochrome black -T indicator. Titrate the wine - red coloured solution with EDTA from the burette until
the colour steel blue appears at the end point. Repeat the titration for concordant values. Let the titre value be
V 2ml.



DETERMINATION OF PERMANENT HARDNESS

Take 100ml of hard water sample in a 500ml beaker and boil gently for about 1hour. Cool, filter it into a
100ml standard flask and make the volume up to the mark. Take 20ml of this solution and proceed it in the same
way as in titration (I). The volume of EDTA consumed corresponds to the permanent hardness of the water
sample. Let the titre value be V 3ml. Temporary hardness is calculated by subtracting permanent hardness from
total hardness.





















18




DETERMINATION OF PERMANENT HARDNESS
BOILED SAMPLE WATER Vs Std. EDTA Indicator: EBT


S.No.
Volume of boiled
hard water (ml)
Burette Reading (ml) Volume of
EDTA
(ml)

Concordant value

Initial Final



CALCULATION OF PERMANENT HARDNESS


Volume of EDTA consumed V 3 = ---------------------ml

1ml of EDTA = 20 / V 1 mg of CaCO 3

V 3ml of EDTA = 20 / V 1 x V 3 mg of CaCO 3

(i.e) 20 ml of boiled sample hard water = 20 / V 1 x V 3 mg of CaCO 3

Then 1000ml of boiled water sample = 20 / V 1 x V 3 / 20 * 1000mg of CaCO 3

= 1000 x V 3 / V 1 mg of CaCO 3

permanent hardness of boiled water sample = -----------------ppm

Temporary hardness of the given water sample = Total hardness ? Permanent hardness

= ------------------ppm

19







RESULT

(i) Total hardness of the given sample water = -------------- ppm.
(ii) Permanent hardness of the given sample water = --------------- ppm.
(iii) Temporary hardness of the given sample water = ----------------ppm.







VIVA-VOCE

1. Define ? Hard water
2. What is the structure of EDTA?
3. How will you calculate temporary hardness?
4. What is the role of the buffer in EDTA titration?
5. What is the permissible limit of hardness in drinking water?
6. Name the hardness producing ions present in water.
7. Name two salts which are responsible for temporary hardness.
8. Why is CaCO 3 taken as the standard?
9. Write the expansion of EDTA.
10. What is meant by EBT?











20





SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II
Standardisation of
AgNO 3
Estimation of Chloride
Burette solution

AgNO 3 solution

Std. AgNO 3 solution

Pipette solution

20ml std KCl solution

20 ml water sample

Indicator

1ml K 2CrO 4

1ml K 2CrO 4


End point

yellow to reddish brown

yellow to reddish brown

Titration I
Std. AgNO3 Vs KCl Indicator: Potassium Chromate













CALCULATION

Volume of KCl (V 1) = ------- ml

Strength of KCl (N 1) = ------- N

Volume of Silver Nitrate (V 2) = -------- ml

Strength of Siver Nitrate V 1N 1
N 2 =
V 1

= --------------------- N

S.No.
Volume of KCl
(ml)
Burette Reading (ml)
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

21




Expt.No. 3 ESTIMATION OF CHLORIDE CONTENT IN WATER
(ARGENTOMETRIC METHOD)
AIM
To estimate the amount of chloride present in given water sample by Argentometric method (Mohr?s
method). You are provided with standard solution of NaCl of strength --------N and a approximately N/10 solution of
Silver nitrate.

PRINCIPLE
The Chloride ion in the form of NaCl, KCl, CaCl 2, MgCl 2 etc., present in the water sample can be estimated
by Argentometric method or known as Mohr?s method. It is an example for precipitation titration. The reaction
between std. Sodium chloride and Silver nitrate is given below.
AgNO 3 + NaCl ? AgCl ? + NaNO 3
The completion of reaction can be observed by employing potassium chromate as the indicator. The end
point is the colour change from yellow to reddish brown due to the following reaction.
2AgNO 3 + K 2CrO 4 ? Ag 2CrO 4 ? + 2KNO 3
Potassium chromate indicator will not be precipitated as silver chromate until all the chlorides in the solution
have been precipitated as AgCl Since a precipitation reaction takes place in preference, this reaction takes place
only at the end point.

PROCEDURE
TITRATION I: STANDARDISATION OF SILVER NITRATE
Pipette out 20ml of standard sodium or potassium chloride solution into a clean conical flask. Add 1ml of 5%
K 2CrO 4 indicator, as the solution turns yellow in colour. Titrate it against silver nitrate solution taken in the burette.
Observe the nearness of the end point through the formation of coagulated silver chloride precipitate at the bottom
of the flask. Now add the silver nitrate drop by drop until the solution gets a faint reddish brown tinge. Repeat the
titration for concordant value. Let the volume of silver nitrate be V 2ml.





22






TITRATION - II

Std AgNO3 Vs WATER SAMPLE Indicator: Potassium Chromate













CALCULATION

Volume of Silver Nitrate (V 3) = ------------ ml

Strength of Siver Nitrate (N 3) = ------------- N

Volume of Water sample (V 4) = -------------- ml

Strength of Water sample V 3 N 3
(N 4) =
V 4

= ----------------- N

Amount of Chloride ion present in 1000 ml of the water sample = Equivalent mass of HCl X 1000


= N 4 x 35.46 x 1000


= -----------------mg/l







S.No.
Volume of water
sample (ml)
Burette Reading
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

23





TITRATION - II
ESTIMATION OF CHLORIDE ION

Pipette out 40 ml of the given water sample into a clean conical flask.To this sample add 1ml of 5% K 2CrO 4
indicator and titrate it against the standardized silver nitrate solution taken in the burette and continue the titration
until the solution produces a reddish brown colour. Note down the end point and repeat the titration for
concordance. Let the volume be V 3ml.







RESULT

The amount of chloride ion present in the water sample = ----------------- mg/l.




VIVA-VOCE

1. Why is this method known as Argentometric method?
2.
What is the chemical reaction between AgNO 3 and Cl
-
ions present in water?

3.
What is the form of Chloride ion present in water?

4. What is the reaction between AgNO 3 and K 2CrO 4 ?
5. What is the name of the method used in this titration?
6. Name the link solution used in the determination.
7. Name the solution used to standardize AgNO 3.
8. What is the indicator used in the determination?
9. How will you calculate the amount of chloride ion in the given solution?
10. What is the colour change in the titration?




24




SHORT PROCEDURE


CONTENTS

TITRATION I

TITRATION II
Burette solution

Std Sodium Hydroxide

Std Sodium Hydroxide

Pipette solution

20 ml hydrochloric acid 20 ml hydrochloric acid
Additional solution


20 ml distilled water

20 ml distilled water


End point



Sudden increase in pH
pH gradual increase

Equivalent Weight of HCl = 36.5







ROUGH GRAPH FAIR GRAPH











pH
? pH/ ? V





Volume of NaOH
(ml)
Volume of NaOH
(ml)





25



Expt. No. 4 DETERMINATION OF STRENGTH OF HCl by pH METRY

AIM
To determine the strength of given HCl by pH metry. A standard solution of 0.1N NaOH is provided.

PRINCIPLE
The pH of a solution is related to H
+
ion concentration by the following formula.

. pH = -log [ H
+
]

pH of a solution is indirectly related to H
+
ion concentration. When NaOH is added slowly to HCl, H
+
ions
get neutralized by OH
-
ions. The pH increases slowly.

H
+
+ Cl
-
+ Na
+
+ OH
-
? Na
+
+ Cl
-
+H 2O

When all H
+
ions of HCl are neutralized at the end point, addition of NaOH causes high increase in pH
because of the addition of excess OH
-
ions.

MATERIALS REQUIRED
pH meter, Glass electrode, Burette, Pipette, Std.NaOH, approximately N/10 HCl .

PROCEDURE

The burette is washed with distilled water, rinsed with the given std. Sodium hydroxide and filled with the
same solution. Exactly 10ml of the given HCl solution is pipetted out into a clean beaker. It is then diluted to 50ml
with distilled water. A glass electrode is dipped into the solution and its terminals are connected to a pH meter.

26

TITRATION - I
S.No Volume of
NaOH (ml)
pH
1

2

3

4

5

6

7

8

9

10


TITRATION - II



CALCULATION

Volume of NaOH (V 1) = ------------------- ml ( titre value)
Strength of NaOH (N 1) = ------------------- N
Volume of HCl (V 2) = ------------------ml
Strength of HCl (N 2) = ------------------ N
N 2 = V 1 N 1 / V 2
Strength of HCl = -------------------- N
Amount of HCl present in 1000ml of the given solution = Strength x equivalent weight of HCl
= ------------------ X 36.5
= --------------------- g
S.No Volume of
NaOH (ml)
pH
11

12

13

14

15

16

17

18

19

20

S.No
Volume of
NaOH (ml)
pH ?pH ?V ?pH / ?V
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
27



Now NaOH is gradually added from the burette to HCl taken in the beaker. pH of the solution is noted for
each addition of NaOH. This process is continued until 5 readings are taken after the end point.
A fair titration is performed to find the exact end point.





RESULT

(i) Strength of the given HCl solution = ---------------- N
(ii) Amount of HCl present in a litre of the solution = ---------------- g


VIVA-VOCE

1. What is meant by pH?
2. What is the name of the reference electrode used ?
3. Why does pH value increase suddenly at the end point?
4. What is the indicator used in the titration?
5. What is the pH range of human blood?
6. What is the unit of pH?
7. How will you calculate the amount of HCl?
8. How is glass electrode represented?
9. Why is glass electrode known as ion selective electrode?
10. What is the chemical reaction involved in this titration?





28




SHORT PROCEDURE


CONTENTS
TITRATION
Burette solution

Std Sodium Hydroxide

Pipette solution

20 ml mixture of acid (HCl+ CH 3COOH)


Additional solution

20 ml distilled water


End point

Conductivity decreases-slowly increases-Sudden increase



Equivalent Weight of HCl = 36.5


Equivalent Weight of CH 3COOH = 60



MODEL GRAPH


Conductance
Volume of NaOH
Mixture of Acids






29




Expt. No. 5 CONDUCTOMETRIC TITRATION OF MIXTURE
OF ACIDS

AIM
To determine the amount of a strong acid and a weak acid present in the given solution.

PRINCIPLE

Solution of electrolytes conducts electricity due to the presence of ions. Since specific conductance of a
solution is proportional to the concentration of ions in it, conductance of the solution is measured during the titration.

HCl + NaOH ? NaCl + H 2O (I neutralization)

CH 3COOH + NaOH ? CH 3COONa + H 2O (II neutralization)

When a solution of HCl is treated with NaOH the fast moving hydrogen ions are progressively replaced by
slow moving sodium ions. As a result conductance of the solution decreases. This decrease will take place until the
first neutralisation point is reached. Further addition of alkali results in formation of sodium acetate.

Since sodium acetate is stronger than acetic acid conductivity slowly increases until all acetic acid is
completely neutralized.(II Neutralisation) This is due to the presence of fast moving OH
-
ions. Anymore addition of
alkali increases the conductance sharply.

PROCEDURE
The burette is filled with NaOH solution upto zero mark. The given unknown solution (mixture of a weak &
a strong acid) is transferred into a 100ml standard flask and made upto the mark with distilled water. 20ml of the
made up solution is pipetted out into a clean 100ml beaker. The solution is diluted to 20ml using distilled water. A
conductivity cell is dipped into the solution and the terminals are connected to a conductivity meter.
30


TITRATION


CALCULATION OF STRENGTH OF HCl
Volume of NaOH (V 1) = --------------- ml (titre value)
Strength of NaOH (N 1) = ---------------- N
Volume of HCl (V 2) = ------------ ml
Strength of HCl (N 2) = -------------- N

N 2 = V 1 N 1 / V 2
Strength of HCl = ---------------- N
CALCULATION OF STRENGTH OF CH3COOH
Volume of NaOH (V 1) = ------------ ml (titre value)
Strength of NaOH (N 1) = ------------ N
Volume of CH 3COOH (V 2) = ------------ ml
Strength of CH 3COOH (N 2) = ------------ N
N 2 = V 1 N 1 / V 2

Strength of CH 3COOH = ------------ N



S.No

Volume of NaOH
(ml)

Conductance (mho)

14

15

16

17
18
19
20

21
22
23
24
25
26

S.No

Volume of NaOH
(ml)

Conductance (mho)

1
2
3
4
5
6
7
8
9
10
11
12
13
31

The burette solution is added to the unknown solution in the beaker in 0.5 ml increments, the solution is
stirred using a glass rod, and the observed conductance values are read from the meter. The conductance values
show decrease in the initial values, then gradually increases and finally shows a steep increase. The titration hence
shows two end-points (i.e) I neutralization (weak acid) & II neutralization (strong acid).
The accurate end-point is obtained by plotting a graph between observed conductance Vs volume of
NaOH added.

RESULT
The strength of acids present in the given unknown solution are:
a) Strong acid = ---------------- N
b) Weak acid = -----------------N



VIVA-VOCE

1. What is weak acid?
2. How many end points are obtained from the graph? Comment two end points.
3. Why is the conductance increase in the first end point?
4. What mixture of acids used in this titration?
5. Write the neutralization reaction between CH 3COOH and NaOH.
6. What is the solution present in the conductivity cell?
7. What are strong and weak electrolytes?
8. Give an example for strong acid and weak acid.
9. What is the strong electrolyte of weak electrolyte?
10. Give an example for strong base.









32

SHORT PROCEDURE



















ROUGH GRAPH







EMF(mV)






Volume of Potassium dichromate (ml)

FAIR GRAPH









? E / ? V

Volume of Potassium dichromate (ml)




CONTENTS

TITRATION I

TITRATION II
Burette solution

Std Potassium dichromate

Std Potassium dichromate

Pipette solution

10 ml of FAS


10 ml of FAS



Additional
solution

20 ml distilled water+
10 ml of dil H 2SO 4


20 ml distilled water+
10 ml of dil H 2SO 4

End point

Sudden increase in EMF

EMF increases and decreases

Equivalent Weight of Ferrous ion = 55.85

33


Expt. No. 6 ESTIMATION OF FERROUS ION BY POTENTIOMETRIC
TITRATION

AIM
To estimate the amount of ferrous ion present in whole of the given solution potentiometrically. A standard
solution of potassium dichromate of strength -----------N is provided.

PRINCIPLE

Potentiometric titrations depend on measurement of emf between reference electrode and an indicator
electrode. When a solution of ferrous iron is titrated with a solution of potassium dichromate, the following redox
reaction takes place.

6Fe
2+
+ Cr 2O 7
2-
+ 14 H
+
? 6Fe
3+
+ 2Cr
3+
+ 7H 2O

During this titration Fe
2+
is converted in to Fe
3+
, whose concentration increases. At the end point, there
will be a sharp change due to sudden removal of all Fe
2+
ions.
The cell is set up by connecting this redox electrode with a calomel electrode as shown below:

Pt, Fe
2+
, Fe
3+
, II KCl , HgCl 2 (s), Hg

A graph between EMF measured against the volume of potassium dichromate added is drawn and the
end point is noted from the graph.

PROCEDURE

10ml of Ferrous solution is pipetted out into a 100 ml beaker. 10ml of dil.H 2SO 4 and 20ml of distilled water
are added. A platinum electrode and a calomel electrode are dipped into this solution and connected to the
potentiometer. Then 1ml of potassium dichromate is added to the solution and stirred well for 30 seconds. The
EMF is measured and the titration is continued by adding potassium dichromate in 1ml increments till five
measurements after the end point.



34


ROUGH TITRATION



S.No.

Volume of dichromate (ml)

EMF (mV)


1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.





35







A graph is drawn by plotting the emf against the volume of potassium dichromate and the end point range is
fixed.


About 20ml of Ferrous solution is pipetted out and the titration is continued by adding 0.1ml increaments of
potassium dichromate in the end point range. The emf is measured for each 0.1ml after stirring the solution well.


A graph is plotted between emf and the volume of potassium dichromate and also a first derivative graph is
plotted ( ? E/ ? V against vol. of K 2Cr 2O 7). The strength of Ferrous solution and the amount of Ferrous ion present are
calculated from the end point.



























36

FAIR TITRATION

S.No Volume of
Dichromate (ml)
Emf (mV) ?E ?V ?E/?V






















CALCULATION

Volume of Potassim dichromate (V 1) = -------------- ml
Normality of Potassium dichromate (N 1) = --------------- N
Volume of Ferrous sulphate (V 2) = --------------- ml
Normality of Ferrous sulphate (N 2) = --------------- N
Amount of Ferrous ion present in 1000ml of the solution = Normality X Equivalent weight of ferrous ion
= --------------- X 55.85 g

The amount of Ferrous ion present in the given solution = ----------------- g






37









RESULT

The amount of Ferrous ion present in the whole of the given solution = --------------- g.








VIVA-VOCE

1. What is EMF?
2. What is the basic principle of potentiometric titration?
3. Why does EMF increase during the titration?
4. Write the cell representation of the titration.
5. What is redox reaction?
6. What is the purpose of adding sulphuric acid?
7. What are the advantages of potentiometric titration?
8. How will you obtain the end point in the titration?
9. What is the name of the indicator electrode used in this titration?
10. What is the name of the reference electrode used?








38



SHORT PROCEDURE



CONTENTS

TITRATION
Burette solution

Sodium Hydroxide

Pipette solution

20 ml HCl


Additional solution

20 ml distilled water


End point

Decrease in conductance- increase in conductance

Equivalent Weight of HCl = 36.5
















Conductance

Volume of NaOH ( ml)









39


Expt.No. 7 CONDUCTOMETRIC TITRATION OF STRONG ACID
WITH STRONG BASE
AIM

To determine the strength of a strong acid by titrating a strong acid and strong base conductometrically. A
standard solution of NaOH of known strength ---------N is provided.

PRINCIPLE
Solution of electrolytes conducts electricity due to the presence of ions. The specific conductance of a
solution is proportional to the concentration of ions in it. The reaction between HCl and NaOH may be represented
as,
HCl +NaOH ? NaCl + H 2O

When a solution of hydrochloric acid is titrated with NaOH, the fast moving hydrogen ions are
progressively replaced by slow moving sodium ions. As a result conductance of the solution decreases, this
decrease in conductance will take place until the end point is reached. Further addition of alkali raises the
conductance sharply, as there is an excess of hydroxide ions.

A graph is drawn between volume of NaOH added and the conductance of solution. The exact end point
is intersection of the two lines.

PROCEDURE

The given HCl is made up in a 100ml standard flask. 10 ml of this solution is pipetted out in a beaker. The
burette is filled with standard sodium hydroxide upto the mark.

A conductivity cell is dipped into the beaker with HCl solution and connected to the terminals of the
conductivity bridge. About 1ml of STD NaOH is added and stirred well for 30 seconds. The conductance is
measured and the titration is continued till five measurements after the endpoint. A graph is plotted for the
conductance values against the volume of NaOH and the endpoint range is fixed.

40


TABLE



CALCULATION
Volume of Sodium Hydroxide (V 1) = ------------- ml
Normality of Sodium Hydroxide (N 1) = ------------- N
Volume of Strong acid (V 2) = ------------- ml
Normality of Strong acid (N 2) = V 1 N 1
V 2

The strength of the given strong acid = ------------- N




S.NO
Volume of NaOH
(ml)
Conductance
(mho)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
41

The above titration is repeated again and the exact endpoint is found out by adding in increments of 0.1ml
of NaOH in the end point range and continued after endpoint upto five readings.
A graph is plotted with the conductance values against the volume of NaOH and then the strength of the
strong acid is found out.


RESULT

The strength of the given strong acid is found to be = --------------- N







VIVA-VOCE

1. What is the basic principle of conductometric titration?
2. Why is conductance decreased and increased during the titration?
3. What is conductance mention its unit?
4. Give some examples for Strong acids and Strong bases.
5. Write the reaction between HCl and NaOH.
6. What is meant by strong base?
7. Explain why HCl is a strong acid?
8. Explain why the strength of burette solution is always greater than the pipette solution in conductometric
titration.
9. What is the equivalent weight of HCl and NaOH?
10. Write the formula that is used to calculate the amount of HCl.











42

ESTIMATION OF COPPER

Alloy solution Vs Std. Na2S2O3 (Thio) Indicator: Starch

S.No.
Volume of
Alloy Solution
(ml)
Burette Reading (ml) Volume of
Thio
(ml)
Concordant value
(ml)
Initial Final

1.

2.

3.












CALCULATION
Volume of Na 2S 2O 3 V 1 = ------------- ml

Strength of Na 2S 2O 3 N 1 = ------------- N

Volume of brass solution V 2 = ------------- ml

Strength of brass solution N 2 = ------------- ?

= V 1 x N I / /V 2

= -------------

Strength of copper solution is = ------------- N



















43


Expt.No.8 ESTIMATION OF COPPER IN BRASS
AIM
To estimate the amount of copper present in the given sample of brass.

PRINCIPLE
Brass is an alloy with 55% copper and 33% zinc and small amount of lead and aluminum. Brass is dissolved
in conc. nitric acid to convert copper present in the alloy to cupric ions. Then copper is estimated iodometrically by
titrating the iodine that was liberated against standard sodium thio sulphate solution using starch as indicator.

2 Cu
2+
+ 4I
-
? 2 CuI + I2
I 2 + 2 Na 2S 2O 3 ? Na 2S 4O 6 + 2NaI

CHEMICALS REQUIRED
0.1N Potassium dichromate, 0.1N sodium thio sulphate, 0.01M EDTA, Con. HNO 3 , , KI, EBT,
NH 3OH / NH 4Cl buffer, Starch.

PROCEDURE
PREPARATION OF BRASS ALLOY SOLUTION

About 0.2g of the sample of brass was weighed accurately and transferred into a clean dry 250ml beaker. To
this about 10ml of con. Nitric acid was added and allowed to boil for a small interval of time till the alloy was dissolved.
This was cooled, diluted with water and made upto 250 ml in a standard flask.

TITRATION I
STANDARDIZATION OF Na2S2O3 WITH K2Cr2O7 SOLUTION
20ml of the standard potassium dichromate solution is pipetted out into a conical flask. 20ml of dil.sulphuric
acid and 10ml of 10% KI are added. The liberated iodine is titrated against sodium thio sulphate taken in the burette till
the colour changes to yellowish green. 1ml of starch is added till the colour changes from blue to light green colour.
Titration is repeated for concordance.
44



CALCULATION


Amount of copper in 1lt of given brass solution = Strength of solution x Eq. Wt of Cu


= ------------------ N x 63.5

= -------------------------

So, Amount of copper in 100ml of given brass solution = ------------------- N x 63.5 x 100 / 1000



ie, ------------g of brass contains = -------------------- g of copper


therefore, % of copper in the given brass sample = ------------------- g x 100


= ------------------ g of brass


= ------------------------ %























45


TITRATION II

ESTIMATION OF COPPER

The brass solution is transferred into the 100ml standard flask and 10ml of dil. sulphuric acid is added and
made up to the mark using distilled water.

20ml of the alloy solutionis pipetted out into a conical flask. To this aqueous ammonia is added in drops till
a blue precipitate of Cu(OH) 2 is formed. One or two drops of acetic acid is added to dissolve the precipitate. To
this 10ml of 10% KI is added and titrated against standard thio sulphate using starch as indicator. The end point is
the disappearance of blue colour and appearance of green colour.



RESULT

The given sample of brass was found to contain copper = ------------- %





VIVA-VOCE



1. What is the composition of brass?
2. What is meant by iodometry?
3. What is the principle used in t his method?
4. What is the role of K 2Cr 2O 7?
5. What is the colour change in this titration?
6. Write the chemical reactions involved in this experiments?
7. How will you find out % of copper in brass?
8. What is the role of indicator?
9. What is the equivalent weight of copper?
10. What is the role of adding aqueous ammonia?


46


SHORT PROCEDURE
Standard solutions are prepared by the dilution of the given stock solution. The flasks are numbered and
the solutions are prepared according to the following table using different glass pipettes.



Flask number

1 2 3 4 5 6
Vol. of pipette to use 1 1 2 10 10 10
Vol. of Na stock solution to pipette 0.5 1 2 4 6 8
Conc. of solution obtained (?g/ml) 5 10 10 40 60 80



MODEL GRAPH








ABSORBANCE






CONCENTRATION








47

Expt. No 9 ESTIMATION OF SODIUM BY USING
FLAME PHOTOMETER
AIM
To estimate the amount of sodium present in whole of the given solution.

APPARATUS REQUIRED
1. Flame photometer FLAPHO or Eppendorf.
2. Stock solutions of Na+ and K+, C = 1 mg/ml.
3. 6 numbered 100 ml volumetric flasks.
4. Glass pipettes: 1, 2, 10 ml.

MEASUREMENT PROCEDURE

1. The flame photo meter is switched on.
2. The instrument is kept for warming.
3. Distilled water is fed into the instrument.
4. The element Na is selected by turning the selector ?Elementwahl?.
5. The outer knob ?Messbereich? is turned into position ?100?. The ?Kompensaton I? knob is pulled slightly
out and adjusted to 0. The ?Kompensation I? knob is pressed back. 0 reading is adjusted with
?Kompensation II? if necessary.
6. The most concentrated standard solution (solution number 6) is aspirated and is adjusted to 350 (on
uppermost scale) using inner ?Messbereich? knob.
6. Distilled water is aspirated till instrument reads 0.
7. The standard solutions no. 1, 2, 3, test solution, and then standards 4, 5, 6 are aspirated.
The results are recorded.
8. Distilled water is aspirated for at least 5 minutes to clean the system(FLAPHO flame photometer).
(FLAPHO is a dual channel instrument, which measures concentrations of Na simultaneously).







48



TABULATION


Flask No.

Concentration

Absorbance

1


2


3


4


5


6

Unknown Solution
X




















49




CALCULATION

1. The calibration curves are drawn for sodium and potassium on a sheet of millimeter-
paper. The concentrations are used as abscissa and instrument readouts as ordinate
values.
2. The concentration of sodium and potassium ions in test solution are found from
calibration curves.

RESULT

The amount of sodium present in whole of the given solution = ------------- g


VIVA - VOCE

1. What is meant by flame photometry?
2. How will you prepare blank solution?
3. Define ? Absorbance
4. State Beer ? Lamberts law.
5. What is the absorbance of sodium?
6. How will you find out unknown concentration of solution?
7. What is meant by wavelength?
8. How will you calibrate the instrument?
9. What is meant by flame emission spectroscopy?
10. Distinguish between absorption and emission spectrum.






50

LIST OF PROJECTS
1. Photo catalysis and water purification and electricity generation
2. The effect of acid rain on marigold plants
3. Using microorganisms (green algae) to bioremediate a source of waste water.
4. The effect of water hardness on the germination of marigold seeds
5. Turn milk into plastic!
6. Find out which household organic waste produce more biogas
7. What makes food decay faster?
8. Obesity: how greasy are your potato chips?
9. The effects of ph level on apple juice fermentation
10. Why does organic milk last so much longer than regular milk? [
11. How sugar content changes in ripening fruit
12. Do oranges lose or gain vitamin c after being picked?
13. Measuring glucose in your food
14. Determine if turmeric can prevent the growth of bacteria which cause foodborne illnesses.
15. What is the effect of antioxidants (vitamins a, e, c) on cells?
16. Will antioxidant supplements help you live longer?
17. Can cloning make a better plant?
18. Biotechnology in the food industry
19. Build a simple burglar alarm
20. Build and demonstrate a homemade fuel cell.
21. Demonstrate the energy stored inside a peanut
22. Increasing the useful lifetime of solar panels
23. The effect of fertilizers on algal growth
24. Determine the effects of neem tree extracts as antibacterial and antifungal agents as well as a pesticidal
agent.
25. Compare short term memory according to gender and age.
26. Which recipe will create the biggest bubbles?
27. Do twins have identical or similar fingerprints?
28. How do plants grow in different environments?
29. Reusable water-powered battery
30. Build a solar toy car and explain its operation.
31. Demonstrate the greenhouse effect in a jar.
FirstRanker.com - FirstRanker's Choice



?



DEPARTMENT OF
SCIENCE AND HUMANITIES

I SEMESTER - R 2017

BS8161 CHEMISTRY LABORATORY







Name : _______________________________________
Register No : _______________________________________
Section : _______________________________________


LABORATORY MANUAL
1






College of Engineering is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.


? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of Academic Excellence in pursuit of Technical Education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and
soul














VISION
MISSION
2





3


PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)
1. Fundamentals
To provide students with a solid foundation in Mathematics, Science and fundamentals of engineering,
enabling them to apply, to find solutions for engineering problems and use this knowledge to acquire higher
education
2. Core Competence
To train the students in chemistry practicals so that they apply their knowledge and training to compare,
and to analyze various engineering industrial problems to find solutions
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice this enables
them to find solutions for the real time problems in industry, and to design products
4. Professionalism
To inculcate professional and effective communication skills, leadership qualities and team spirit in the
students to make them multi-faceted personalities and develop their ability to relate engineering issues to
broader social context
5. Lifelong Learning/Ethics
To demonstrate and practice ethical and professional responsibilities in the industry and society in the
large, through commitment and lifelong learning needed for successful professional career






4


PROGRAMME OUTCOMES (POs)
To demonstrate and apply knowledge of Mathematics, Science and engineering fundamentals in the following
experiments.
1 .To estimate HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. To determine total, temporary & permanent hardness of water by EDTA method.
3. To determine DO content of water sample by Winkler?s method.
4. To determine chloride content of water sample by Argentometric method.
5. To estimate copper content of the given solution by Iodometry.
6. To determine strength of given hydrochloric acid using pH meter.
7. To determine strength of acids in a mixture of acids using conductivity meter.
8. To determine iron content of the given solution using potentiometer.
9. To estimate iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. To estimate sodium and potassium present in water using flame photometer.
11. To determine molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. To determine Pseudo first order kinetics ? ester hydrolysis.
13. To determine Corrosion experiment ? weight loss method.
14. To estimate CMC.
15. To estimate Phase change in a solid.
16. To determine strength of strong acid vs strong base using conductivity meter.











5

BS8161 - CHEMISTRY LABORATORY
SYLLABUS


? To make the student to acquire practical skills in the determination of water quality
parameters through volumetric and instrumental analysis.

? ???? ??? ???? ?? ???? ? ? ?To acquaint the students with the determination of molecular weight of a polymer by
viscometery.

LIST OF EXPERIMENTS:
1. Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in water
sample.
2. Determination of total, temporary & permanent hardness of water by EDTA method.
3. Determination of DO content of water sample by Winkler?s method.
4. Determination of chloride content of water sample by Argentometric method.
5. Estimation of copper content of the given solution by Iodometry.
6. Determination of strength of given hydrochloric acid using pH meter.
7. Determination of strength of acids in a mixture of acids using conductivity meter.
8. Estimation of iron content of the given solution using potentiometer.
9. Estimation of iron content of the water sample using spectrophotometer
(1, 10- Phenanthroline / thiocyanate method).
10. Estimation of sodium and potassium present in water using flame photometer.
11. Determination of molecular weight of polyvinyl alcohol using Ostwald viscometer.
12. Pseudo first order kinetics ? ester hydrolysis.
13. Corrosion experiment ? weight loss method.
14. Determination of CMC.
15. Phase change in a solid.
16. Conductometric titration of strong acid vs strong base.




? The students will be outfitted with hands-on knowledge in the quantitative chemical
analysis of water quality related parameters.
COURSE OBJECTIVES
COURSE OUTCOMES
6


INDEX [ SEMESTER ? I ]


S.No.



Date


Experiment

Date of
submission



Mark


Signature

1.

Estimation of HCl using Na 2CO 3 as
primary standard and Determination of
alkalinity in water sample.



2.


Determination of total, temporary &
permanent hardness of water by EDTA
method.



3.


Determination of chloride content of water
sample by argentometric method.



4.


Determination of strength of given
hydrochloric acid using pH meter.



5.


Determination of strength of acids in a
mixture of acids using conductivity meter.



6.


Estimation of iron content of the given
solution using potentiometer.



7.





Conductometric titration of strong acid Vs
strong base.



8.



Estimation of copper content of the given
solution by Iodometry


9.
Estimation of sodium and potassium
present in water using flame photometer




7




CONTENTS


S.No.


NAME OF EXPERIMENT

PAGE
No.
SEMESTER - I
1.
Estimation of HCl using Na 2CO 3 as primary standard and Determination of alkalinity in
water sample.
09
2. Determination of total, temporary & permanent hardness of water by EDTA method. 15
3. Determination of chloride content of water sample by Argentometric method. 21
4. Determination of strength of given hydrochloric acid using pH meter. 25
5. Determination of strength of acids in a mixture of acids using conductivity meter. 29
6. Estimation of iron content of the given solution using potentiometer. 33
7. Conductometric titration of strong acid Vs strong base.

39


42

8


Estimation of copper content of the given solution by Iodometry 43
9 Estimation of sodium and potassium present in water using flame photometer 47






8



SHORT PROCEDURE:

CONTENTS
TITRATION
Estimation of alkalinity in water sample
(Std HCl Vs water sample)

Burette solution

Std. HCl


Pipette solution

Water sample


Indicator


(i) Phenolphthalein
(ii) Methyl orange


End point

(i) Disappearance of pink colour
(ii) Appearance of reddish orange colour






Relationship
between P &M
Nature of alkalinity
Amount of individual
alkalinities
OH
-
HCO 3
-


CO 3
2-

P = M

only OH
-

P or M

?
0.0

0.0


2P = M

only CO 3
2-


2P or M


0.0


0.0


?

P =0, M?0

only HCO 3
-



M



0.0



?

0.0


2P > M


OH
-
&CO 3
2-


OH
-
= 2P-M
CO 3
2-
= 2(M-P)


?

0.0

?

P < ? M




HCO 3
-
&CO 3
2-


HCO 3
-
= M-2P
CO 3
2-
= 2P

0.0 ? ?




9





Expt. No. 1 DETERMINATION OF ALKALINITY IN WATER
AIM
To determine the type and amounts of alkalinity in the given water sample. A standard solution of Na 2CO 3
of strength ____N is given.

PRINCIPLE
Alkalinity in water is due to the presence of soluble hydroxides, bicarbonates and carbonates.
Determination of various types and amounts of alkalinity is easily carried out by titration with standard HCl
employing the indicators phenolphthalein and methyl orange independently or in succession.

The following reactions occur when different types of alkalinity are neutralized with acid.

OH
?
+ H
+
? H 2O completed at pH 8.2-9.0 ----- (1)

CO 3
2 ?
+ H
+
? HCO 3
?
----- (2)

HCO 3
?
+ H
+
? (H 2CO 3) ? H 2O + CO 2, completed at pH 4.2-5.5 ----- (3)

Neutralisation (1) & (2) will be notified by phenolphthalein end-point while all the three will be

accounted by
methyl orange end-point. Bicarbonate in eqn. (3) may be due to the existence of soluble free bicarbonate salts and
bicarbonates resulting from half neutralization of soluble carbonates (eqn. (2))

Various steps to be followed

a) A known volume of water sample is titrated against std. HCl using first phenolphthalein indicator till
end-point (P) and the titration is continued without break using methyl orange indicator till the end-
point (M).



10


Titration

Estimation of Alkalinity in water sample

Standard HCl Vs Water sample Indicator: 1. Phenolphthalein
2. Methyl Orange


S.No.
Volume
of water
sample (ml)
Burette Reading
Concordant value

Initial Phenolphthalein End
Point (P)
Methyl Orange End
Point (M)

1

2






CALCULATION

Hydroxide ion alkalinity
Volume of HCl (2P-M) = ???????ml

Strength of HCl = ???????? N

Volume of water sample = ???????...ml

Strength of water sample = Volume of HCl (2P-M) x Strength of HCl
Volume of water sample

=

? Hydroxide ion alkalinity in terms of
CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ??????.mg/l







11




b) From the magnitudes of the P & M, the nature of alkalinity can be arrived as follows:

(i) P = M => Presence of only OH
-

(ii) 2P = M => Presence of only CO 3
2-

(iii) P =0, M=0 => Presence of only HCO 3
-
(iv) 2P > M => Presence of OH
-
& CO 3
2-
(v) 2P < M => Presence of HCO 3
-
& CO 3
2-

(Mixture of OH
-
& HCO3
-
is not listed since they do not exist together and are considered equivalent to CO 3
2-
).

PROCEDURE
TITRATION
ESTIMATION OF ALKALINITY IN WATER SAMPLE

Exactly 20 ml of water sample is pipetted out into a clean conical flask. Few drops of phenolphthalein
indicator are added and titrated against a standardized HCl taken in the burette. The end point is the
disappearance of pink colour, which is noted as P. Few drops of methyl orange indicator is added to the same
solution. The solution turns to yellow. The titration is continued further by adding same HCl without break till the
end point is reached. The end point is the colour change from yellow to reddish orange.

The experiment is repeated to get concordant values. From the magnitudes of P & M values, the type of
alkalinity present in the water sample is inferred and the individual amounts are calculated and reported.










12


Carbonate ion alkalinity

Volume of HCl 2 (M ? P) = ??? ????????ml

Strength of HCl = ??.?????..???...N

Volume of water sample =........................................ml

Strength of water sample = Volume of HCl 2 (M ? P) x Strength of HCl
Volume of water sample

= ???????????.. N




? Carbonate ion alkalinity
in terms of CaCO 3 equivalent = Strength of water sample x Equivalent weight of CaCO 3 x 1000

= Strength of water sample x 50 x 1000

= ???????????mg/l

















13





RESULT

1) The type of alkalinity present in the water sample = -------------------------ions.

2) The individual amounts of alkalinity present in the water sample:
Hydroxide ion alkalinity

= ----------------- ppm
Carbonate ion alkalinity = ------------------ ppm
Bicarbonate ion alkalinity = ----------------- ppm





VIVA-VOCE


1. What is meant by alkalinity?
2. What are the ions responsible for alkalinity?
3. Why OH
-
and HCO 3
?
ions cannot exist together in water?
4. What are the ions responsible for alkalinity when 2P > M?
5. What is the pH range for both in acidic and basic solutions?
6. What is the colour of phenolphthalein in an acid and in an alkaline solution?
7. What is the purpose of using two indicators in same titration?
8. What are the possible combinations of ions for alkalinity?
9. How is the amount of alkalinity expressed?
10. What are the types of indicator used in this experiment?







14

SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II TITRATION III
Standardisation of
EDTA
(EDTA Vs Std
Hard water)
Determination of
total hardness
(Std EDTA Vs Hard
water sample)
Determination of
permanent hardness
(Std EDTA Vs Boiled
Hard water sample)

Burette solution

EDTA solution

EDTA solution

EDTA solution

Pipette solution

20ml Std. hard water

20 ml hard water sample

20ml boiled hard water sample

Indicator

2 drops of EBT

2 drops of EBT

2 drops of EBT

Additional soln.


Ammoniacal Buffer
solution (5ml)

Ammoniacal Buffer solution
(5ml)

Ammoniacal Buffer solution
(5ml)
End point Wine - red to Steel blue Wine - red to steel blue Wine - red to Steel blue




STANDARDISATION OF EDTA
Titration - I
Std. HARD WATER Vs EDTA Indicator: EBT

S. No.
Volume of std hard
water (ml)
Burette Reading Volume of
EDTA
(V 1) (ml)
Concordant value

Initial

Final



Volume of std .hard water taken = 20 ml
Volume of EDTA consumed (V 1) = --------------- ml
1 ml of std.hard water = 1mg of CaCO 3
20 ml of std hard water = 20 mg of CaCO 3

V 1 ml of EDTA solution containing 20 mg of CaCO 3
1 ml of EDTA solution = 20 / V 1 mg of CaCO 3
= -----------------------mg of CaCO 3


15

Expt. No. 2 DETERMINATION OF TOTAL, TEMPORARY AND
PERMANENT HARDNESS OF WATER

AIM
To estimate the amount of total, temporary & permanent hardness in the given sample of water.

PRINCIPLE
The estimation is based on the complexometric titration.

(i) Total hardness of water is estimated by titrating against EDTA using EBT indicator.
EBT+M ?[EBT-M] (unstable complex)
(EBT-M) (Unstable complex) +EDTA ? [EDTA-M] (stable complex) +EBT
EBT indicator forms wine- red colored complex with metal ions present in water. On addition of EDTA
metal ions preferably forms complexes with EDTA and steel blue EBT indicator is set free. Therefore
change of colour from wine- red to steel blue denotes the end point.

(ii) Temporary hardness is removed by boiling the water.
Ca (HCO 3) 2 ? CaCO 3 +CO 2 ?+H 2O
Mg (HCO 3) 2 ? Mg(OH) 2 +2CO 2 ?
The precipitate is filtered and the remaining permanent hardness is estimated using EDTA.

PROCEDURE

TITRATION ? I
STANDARDISATION OF EDTA

Pipette out 20ml of standard hard water into a 250ml conical flask. Add 5ml of buffer solution and 3
drops of eriochrome black T indictor. Titrate the solution with EDTA from the burette until the colour
changes from wine- red to steel blue at the end point. Repeat the titration for concordant values. Let the
titre value be V 1ml.


16


Titration-II
SAMPLE HARD WATER Vs Std EDTA Indicator: EBT

S.No. Volume of sample
hard water (ml)
Burette Reading Volume of
EDTA
(V 2) (ml)
Concordant value

Initial

Final




CALCULATION

Calculation of total hardness


Volume of EDTA consumed (V 2) = ------------------------- ml
1ml of EDTA = 20 / V 1 mg of CaCO 3
V 2 ml of EDTA = 20 / V 1 x V 2 mg of CaCO 3

( i.e), If 20ml of sample hard water contains 20 x V 2 mg of CaCO 3 / V 1

Then 1000ml of water sample = 20 x V 2 x 1000 / V 1 x 20 mg of CaCO 3

= 1000 x V 2 / V 1 mg of CaCO3

Total hardness of given water sample = ---------------------ppm









17



DETERMINATION OF TOTAL HARDNESS

Pipette out 20ml of sample hard water into a clean conical flask. Add 5ml of buffer solution and 4 -5
drops of Eriochrome black -T indicator. Titrate the wine - red coloured solution with EDTA from the burette until
the colour steel blue appears at the end point. Repeat the titration for concordant values. Let the titre value be
V 2ml.



DETERMINATION OF PERMANENT HARDNESS

Take 100ml of hard water sample in a 500ml beaker and boil gently for about 1hour. Cool, filter it into a
100ml standard flask and make the volume up to the mark. Take 20ml of this solution and proceed it in the same
way as in titration (I). The volume of EDTA consumed corresponds to the permanent hardness of the water
sample. Let the titre value be V 3ml. Temporary hardness is calculated by subtracting permanent hardness from
total hardness.





















18




DETERMINATION OF PERMANENT HARDNESS
BOILED SAMPLE WATER Vs Std. EDTA Indicator: EBT


S.No.
Volume of boiled
hard water (ml)
Burette Reading (ml) Volume of
EDTA
(ml)

Concordant value

Initial Final



CALCULATION OF PERMANENT HARDNESS


Volume of EDTA consumed V 3 = ---------------------ml

1ml of EDTA = 20 / V 1 mg of CaCO 3

V 3ml of EDTA = 20 / V 1 x V 3 mg of CaCO 3

(i.e) 20 ml of boiled sample hard water = 20 / V 1 x V 3 mg of CaCO 3

Then 1000ml of boiled water sample = 20 / V 1 x V 3 / 20 * 1000mg of CaCO 3

= 1000 x V 3 / V 1 mg of CaCO 3

permanent hardness of boiled water sample = -----------------ppm

Temporary hardness of the given water sample = Total hardness ? Permanent hardness

= ------------------ppm

19







RESULT

(i) Total hardness of the given sample water = -------------- ppm.
(ii) Permanent hardness of the given sample water = --------------- ppm.
(iii) Temporary hardness of the given sample water = ----------------ppm.







VIVA-VOCE

1. Define ? Hard water
2. What is the structure of EDTA?
3. How will you calculate temporary hardness?
4. What is the role of the buffer in EDTA titration?
5. What is the permissible limit of hardness in drinking water?
6. Name the hardness producing ions present in water.
7. Name two salts which are responsible for temporary hardness.
8. Why is CaCO 3 taken as the standard?
9. Write the expansion of EDTA.
10. What is meant by EBT?











20





SHORT PROCEDURE

CONTENTS
TITRATION I TITRATION II
Standardisation of
AgNO 3
Estimation of Chloride
Burette solution

AgNO 3 solution

Std. AgNO 3 solution

Pipette solution

20ml std KCl solution

20 ml water sample

Indicator

1ml K 2CrO 4

1ml K 2CrO 4


End point

yellow to reddish brown

yellow to reddish brown

Titration I
Std. AgNO3 Vs KCl Indicator: Potassium Chromate













CALCULATION

Volume of KCl (V 1) = ------- ml

Strength of KCl (N 1) = ------- N

Volume of Silver Nitrate (V 2) = -------- ml

Strength of Siver Nitrate V 1N 1
N 2 =
V 1

= --------------------- N

S.No.
Volume of KCl
(ml)
Burette Reading (ml)
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

21




Expt.No. 3 ESTIMATION OF CHLORIDE CONTENT IN WATER
(ARGENTOMETRIC METHOD)
AIM
To estimate the amount of chloride present in given water sample by Argentometric method (Mohr?s
method). You are provided with standard solution of NaCl of strength --------N and a approximately N/10 solution of
Silver nitrate.

PRINCIPLE
The Chloride ion in the form of NaCl, KCl, CaCl 2, MgCl 2 etc., present in the water sample can be estimated
by Argentometric method or known as Mohr?s method. It is an example for precipitation titration. The reaction
between std. Sodium chloride and Silver nitrate is given below.
AgNO 3 + NaCl ? AgCl ? + NaNO 3
The completion of reaction can be observed by employing potassium chromate as the indicator. The end
point is the colour change from yellow to reddish brown due to the following reaction.
2AgNO 3 + K 2CrO 4 ? Ag 2CrO 4 ? + 2KNO 3
Potassium chromate indicator will not be precipitated as silver chromate until all the chlorides in the solution
have been precipitated as AgCl Since a precipitation reaction takes place in preference, this reaction takes place
only at the end point.

PROCEDURE
TITRATION I: STANDARDISATION OF SILVER NITRATE
Pipette out 20ml of standard sodium or potassium chloride solution into a clean conical flask. Add 1ml of 5%
K 2CrO 4 indicator, as the solution turns yellow in colour. Titrate it against silver nitrate solution taken in the burette.
Observe the nearness of the end point through the formation of coagulated silver chloride precipitate at the bottom
of the flask. Now add the silver nitrate drop by drop until the solution gets a faint reddish brown tinge. Repeat the
titration for concordant value. Let the volume of silver nitrate be V 2ml.





22






TITRATION - II

Std AgNO3 Vs WATER SAMPLE Indicator: Potassium Chromate













CALCULATION

Volume of Silver Nitrate (V 3) = ------------ ml

Strength of Siver Nitrate (N 3) = ------------- N

Volume of Water sample (V 4) = -------------- ml

Strength of Water sample V 3 N 3
(N 4) =
V 4

= ----------------- N

Amount of Chloride ion present in 1000 ml of the water sample = Equivalent mass of HCl X 1000


= N 4 x 35.46 x 1000


= -----------------mg/l







S.No.
Volume of water
sample (ml)
Burette Reading
Volume of
AgNO 3 (ml)
Concordant
Value
Initial Final

23





TITRATION - II
ESTIMATION OF CHLORIDE ION

Pipette out 40 ml of the given water sample into a clean conical flask.To this sample add 1ml of 5% K 2CrO 4
indicator and titrate it against the standardized silver nitrate solution taken in the burette and continue the titration
until the solution produces a reddish brown colour. Note down the end point and repeat the titration for
concordance. Let the volume be V 3ml.







RESULT

The amount of chloride ion present in the water sample = ----------------- mg/l.




VIVA-VOCE

1. Why is this method known as Argentometric method?
2.
What is the chemical reaction between AgNO 3 and Cl
-
ions present in water?

3.
What is the form of Chloride ion present in water?

4. What is the reaction between AgNO 3 and K 2CrO 4 ?
5. What is the name of the method used in this titration?
6. Name the link solution used in the determination.
7. Name the solution used to standardize AgNO 3.
8. What is the indicator used in the determination?
9. How will you calculate the amount of chloride ion in the given solution?
10. What is the colour change in the titration?




24




SHORT PROCEDURE


CONTENTS

TITRATION I

TITRATION II
Burette solution

Std Sodium Hydroxide

Std Sodium Hydroxide

Pipette solution

20 ml hydrochloric acid 20 ml hydrochloric acid
Additional solution


20 ml distilled water

20 ml distilled water


End point



Sudden increase in pH
pH gradual increase

Equivalent Weight of HCl = 36.5







ROUGH GRAPH FAIR GRAPH











pH
? pH/ ? V





Volume of NaOH
(ml)
Volume of NaOH
(ml)





25



Expt. No. 4 DETERMINATION OF STRENGTH OF HCl by pH METRY

AIM
To determine the strength of given HCl by pH metry. A standard solution of 0.1N NaOH is provided.

PRINCIPLE
The pH of a solution is related to H
+
ion concentration by the following formula.

. pH = -log [ H
+
]

pH of a solution is indirectly related to H
+
ion concentration. When NaOH is added slowly to HCl, H
+
ions
get neutralized by OH
-
ions. The pH increases slowly.

H
+
+ Cl
-
+ Na
+
+ OH
-
? Na
+
+ Cl
-
+H 2O

When all H
+
ions of HCl are neutralized at the end point, addition of NaOH causes high increase in pH
because of the addition of excess OH
-
ions.

MATERIALS REQUIRED
pH meter, Glass electrode, Burette, Pipette, Std.NaOH, approximately N/10 HCl .

PROCEDURE

The burette is washed with distilled water, rinsed with the given std. Sodium hydroxide and filled with the
same solution. Exactly 10ml of the given HCl solution is pipetted out into a clean beaker. It is then diluted to 50ml
with distilled water. A glass electrode is dipped into the solution and its terminals are connected to a pH meter.

26

TITRATION - I
S.No Volume of
NaOH (ml)
pH
1

2

3

4

5

6

7

8

9

10


TITRATION - II



CALCULATION

Volume of NaOH (V 1) = ------------------- ml ( titre value)
Strength of NaOH (N 1) = ------------------- N
Volume of HCl (V 2) = ------------------ml
Strength of HCl (N 2) = ------------------ N
N 2 = V 1 N 1 / V 2
Strength of HCl = -------------------- N
Amount of HCl present in 1000ml of the given solution = Strength x equivalent weight of HCl
= ------------------ X 36.5
= --------------------- g
S.No Volume of
NaOH (ml)
pH
11

12

13

14

15

16

17

18

19

20

S.No
Volume of
NaOH (ml)
pH ?pH ?V ?pH / ?V
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
27



Now NaOH is gradually added from the burette to HCl taken in the beaker. pH of the solution is noted for
each addition of NaOH. This process is continued until 5 readings are taken after the end point.
A fair titration is performed to find the exact end point.





RESULT

(i) Strength of the given HCl solution = ---------------- N
(ii) Amount of HCl present in a litre of the solution = ---------------- g


VIVA-VOCE

1. What is meant by pH?
2. What is the name of the reference electrode used ?
3. Why does pH value increase suddenly at the end point?
4. What is the indicator used in the titration?
5. What is the pH range of human blood?
6. What is the unit of pH?
7. How will you calculate the amount of HCl?
8. How is glass electrode represented?
9. Why is glass electrode known as ion selective electrode?
10. What is the chemical reaction involved in this titration?





28




SHORT PROCEDURE


CONTENTS
TITRATION
Burette solution

Std Sodium Hydroxide

Pipette solution

20 ml mixture of acid (HCl+ CH 3COOH)


Additional solution

20 ml distilled water


End point

Conductivity decreases-slowly increases-Sudden increase



Equivalent Weight of HCl = 36.5


Equivalent Weight of CH 3COOH = 60



MODEL GRAPH


Conductance
Volume of NaOH
Mixture of Acids






29




Expt. No. 5 CONDUCTOMETRIC TITRATION OF MIXTURE
OF ACIDS

AIM
To determine the amount of a strong acid and a weak acid present in the given solution.

PRINCIPLE

Solution of electrolytes conducts electricity due to the presence of ions. Since specific conductance of a
solution is proportional to the concentration of ions in it, conductance of the solution is measured during the titration.

HCl + NaOH ? NaCl + H 2O (I neutralization)

CH 3COOH + NaOH ? CH 3COONa + H 2O (II neutralization)

When a solution of HCl is treated with NaOH the fast moving hydrogen ions are progressively replaced by
slow moving sodium ions. As a result conductance of the solution decreases. This decrease will take place until the
first neutralisation point is reached. Further addition of alkali results in formation of sodium acetate.

Since sodium acetate is stronger than acetic acid conductivity slowly increases until all acetic acid is
completely neutralized.(II Neutralisation) This is due to the presence of fast moving OH
-
ions. Anymore addition of
alkali increases the conductance sharply.

PROCEDURE
The burette is filled with NaOH solution upto zero mark. The given unknown solution (mixture of a weak &
a strong acid) is transferred into a 100ml standard flask and made upto the mark with distilled water. 20ml of the
made up solution is pipetted out into a clean 100ml beaker. The solution is diluted to 20ml using distilled water. A
conductivity cell is dipped into the solution and the terminals are connected to a conductivity meter.
30


TITRATION


CALCULATION OF STRENGTH OF HCl
Volume of NaOH (V 1) = --------------- ml (titre value)
Strength of NaOH (N 1) = ---------------- N
Volume of HCl (V 2) = ------------ ml
Strength of HCl (N 2) = -------------- N

N 2 = V 1 N 1 / V 2
Strength of HCl = ---------------- N
CALCULATION OF STRENGTH OF CH3COOH
Volume of NaOH (V 1) = ------------ ml (titre value)
Strength of NaOH (N 1) = ------------ N
Volume of CH 3COOH (V 2) = ------------ ml
Strength of CH 3COOH (N 2) = ------------ N
N 2 = V 1 N 1 / V 2

Strength of CH 3COOH = ------------ N



S.No

Volume of NaOH
(ml)

Conductance (mho)

14

15

16

17
18
19
20

21
22
23
24
25
26

S.No

Volume of NaOH
(ml)

Conductance (mho)

1
2
3
4
5
6
7
8
9
10
11
12
13
31

The burette solution is added to the unknown solution in the beaker in 0.5 ml increments, the solution is
stirred using a glass rod, and the observed conductance values are read from the meter. The conductance values
show decrease in the initial values, then gradually increases and finally shows a steep increase. The titration hence
shows two end-points (i.e) I neutralization (weak acid) & II neutralization (strong acid).
The accurate end-point is obtained by plotting a graph between observed conductance Vs volume of
NaOH added.

RESULT
The strength of acids present in the given unknown solution are:
a) Strong acid = ---------------- N
b) Weak acid = -----------------N



VIVA-VOCE

1. What is weak acid?
2. How many end points are obtained from the graph? Comment two end points.
3. Why is the conductance increase in the first end point?
4. What mixture of acids used in this titration?
5. Write the neutralization reaction between CH 3COOH and NaOH.
6. What is the solution present in the conductivity cell?
7. What are strong and weak electrolytes?
8. Give an example for strong acid and weak acid.
9. What is the strong electrolyte of weak electrolyte?
10. Give an example for strong base.









32

SHORT PROCEDURE



















ROUGH GRAPH







EMF(mV)






Volume of Potassium dichromate (ml)

FAIR GRAPH









? E / ? V

Volume of Potassium dichromate (ml)




CONTENTS

TITRATION I

TITRATION II
Burette solution

Std Potassium dichromate

Std Potassium dichromate

Pipette solution

10 ml of FAS


10 ml of FAS



Additional
solution

20 ml distilled water+
10 ml of dil H 2SO 4


20 ml distilled water+
10 ml of dil H 2SO 4

End point

Sudden increase in EMF

EMF increases and decreases

Equivalent Weight of Ferrous ion = 55.85

33


Expt. No. 6 ESTIMATION OF FERROUS ION BY POTENTIOMETRIC
TITRATION

AIM
To estimate the amount of ferrous ion present in whole of the given solution potentiometrically. A standard
solution of potassium dichromate of strength -----------N is provided.

PRINCIPLE

Potentiometric titrations depend on measurement of emf between reference electrode and an indicator
electrode. When a solution of ferrous iron is titrated with a solution of potassium dichromate, the following redox
reaction takes place.

6Fe
2+
+ Cr 2O 7
2-
+ 14 H
+
? 6Fe
3+
+ 2Cr
3+
+ 7H 2O

During this titration Fe
2+
is converted in to Fe
3+
, whose concentration increases. At the end point, there
will be a sharp change due to sudden removal of all Fe
2+
ions.
The cell is set up by connecting this redox electrode with a calomel electrode as shown below:

Pt, Fe
2+
, Fe
3+
, II KCl , HgCl 2 (s), Hg

A graph between EMF measured against the volume of potassium dichromate added is drawn and the
end point is noted from the graph.

PROCEDURE

10ml of Ferrous solution is pipetted out into a 100 ml beaker. 10ml of dil.H 2SO 4 and 20ml of distilled water
are added. A platinum electrode and a calomel electrode are dipped into this solution and connected to the
potentiometer. Then 1ml of potassium dichromate is added to the solution and stirred well for 30 seconds. The
EMF is measured and the titration is continued by adding potassium dichromate in 1ml increments till five
measurements after the end point.



34


ROUGH TITRATION



S.No.

Volume of dichromate (ml)

EMF (mV)


1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.





35







A graph is drawn by plotting the emf against the volume of potassium dichromate and the end point range is
fixed.


About 20ml of Ferrous solution is pipetted out and the titration is continued by adding 0.1ml increaments of
potassium dichromate in the end point range. The emf is measured for each 0.1ml after stirring the solution well.


A graph is plotted between emf and the volume of potassium dichromate and also a first derivative graph is
plotted ( ? E/ ? V against vol. of K 2Cr 2O 7). The strength of Ferrous solution and the amount of Ferrous ion present are
calculated from the end point.



























36

FAIR TITRATION

S.No Volume of
Dichromate (ml)
Emf (mV) ?E ?V ?E/?V






















CALCULATION

Volume of Potassim dichromate (V 1) = -------------- ml
Normality of Potassium dichromate (N 1) = --------------- N
Volume of Ferrous sulphate (V 2) = --------------- ml
Normality of Ferrous sulphate (N 2) = --------------- N
Amount of Ferrous ion present in 1000ml of the solution = Normality X Equivalent weight of ferrous ion
= --------------- X 55.85 g

The amount of Ferrous ion present in the given solution = ----------------- g






37









RESULT

The amount of Ferrous ion present in the whole of the given solution = --------------- g.








VIVA-VOCE

1. What is EMF?
2. What is the basic principle of potentiometric titration?
3. Why does EMF increase during the titration?
4. Write the cell representation of the titration.
5. What is redox reaction?
6. What is the purpose of adding sulphuric acid?
7. What are the advantages of potentiometric titration?
8. How will you obtain the end point in the titration?
9. What is the name of the indicator electrode used in this titration?
10. What is the name of the reference electrode used?








38



SHORT PROCEDURE



CONTENTS

TITRATION
Burette solution

Sodium Hydroxide

Pipette solution

20 ml HCl


Additional solution

20 ml distilled water


End point

Decrease in conductance- increase in conductance

Equivalent Weight of HCl = 36.5
















Conductance

Volume of NaOH ( ml)









39


Expt.No. 7 CONDUCTOMETRIC TITRATION OF STRONG ACID
WITH STRONG BASE
AIM

To determine the strength of a strong acid by titrating a strong acid and strong base conductometrically. A
standard solution of NaOH of known strength ---------N is provided.

PRINCIPLE
Solution of electrolytes conducts electricity due to the presence of ions. The specific conductance of a
solution is proportional to the concentration of ions in it. The reaction between HCl and NaOH may be represented
as,
HCl +NaOH ? NaCl + H 2O

When a solution of hydrochloric acid is titrated with NaOH, the fast moving hydrogen ions are
progressively replaced by slow moving sodium ions. As a result conductance of the solution decreases, this
decrease in conductance will take place until the end point is reached. Further addition of alkali raises the
conductance sharply, as there is an excess of hydroxide ions.

A graph is drawn between volume of NaOH added and the conductance of solution. The exact end point
is intersection of the two lines.

PROCEDURE

The given HCl is made up in a 100ml standard flask. 10 ml of this solution is pipetted out in a beaker. The
burette is filled with standard sodium hydroxide upto the mark.

A conductivity cell is dipped into the beaker with HCl solution and connected to the terminals of the
conductivity bridge. About 1ml of STD NaOH is added and stirred well for 30 seconds. The conductance is
measured and the titration is continued till five measurements after the endpoint. A graph is plotted for the
conductance values against the volume of NaOH and the endpoint range is fixed.

40


TABLE



CALCULATION
Volume of Sodium Hydroxide (V 1) = ------------- ml
Normality of Sodium Hydroxide (N 1) = ------------- N
Volume of Strong acid (V 2) = ------------- ml
Normality of Strong acid (N 2) = V 1 N 1
V 2

The strength of the given strong acid = ------------- N




S.NO
Volume of NaOH
(ml)
Conductance
(mho)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
41

The above titration is repeated again and the exact endpoint is found out by adding in increments of 0.1ml
of NaOH in the end point range and continued after endpoint upto five readings.
A graph is plotted with the conductance values against the volume of NaOH and then the strength of the
strong acid is found out.


RESULT

The strength of the given strong acid is found to be = --------------- N







VIVA-VOCE

1. What is the basic principle of conductometric titration?
2. Why is conductance decreased and increased during the titration?
3. What is conductance mention its unit?
4. Give some examples for Strong acids and Strong bases.
5. Write the reaction between HCl and NaOH.
6. What is meant by strong base?
7. Explain why HCl is a strong acid?
8. Explain why the strength of burette solution is always greater than the pipette solution in conductometric
titration.
9. What is the equivalent weight of HCl and NaOH?
10. Write the formula that is used to calculate the amount of HCl.











42

ESTIMATION OF COPPER

Alloy solution Vs Std. Na2S2O3 (Thio) Indicator: Starch

S.No.
Volume of
Alloy Solution
(ml)
Burette Reading (ml) Volume of
Thio
(ml)
Concordant value
(ml)
Initial Final

1.

2.

3.












CALCULATION
Volume of Na 2S 2O 3 V 1 = ------------- ml

Strength of Na 2S 2O 3 N 1 = ------------- N

Volume of brass solution V 2 = ------------- ml

Strength of brass solution N 2 = ------------- ?

= V 1 x N I / /V 2

= -------------

Strength of copper solution is = ------------- N



















43


Expt.No.8 ESTIMATION OF COPPER IN BRASS
AIM
To estimate the amount of copper present in the given sample of brass.

PRINCIPLE
Brass is an alloy with 55% copper and 33% zinc and small amount of lead and aluminum. Brass is dissolved
in conc. nitric acid to convert copper present in the alloy to cupric ions. Then copper is estimated iodometrically by
titrating the iodine that was liberated against standard sodium thio sulphate solution using starch as indicator.

2 Cu
2+
+ 4I
-
? 2 CuI + I2
I 2 + 2 Na 2S 2O 3 ? Na 2S 4O 6 + 2NaI

CHEMICALS REQUIRED
0.1N Potassium dichromate, 0.1N sodium thio sulphate, 0.01M EDTA, Con. HNO 3 , , KI, EBT,
NH 3OH / NH 4Cl buffer, Starch.

PROCEDURE
PREPARATION OF BRASS ALLOY SOLUTION

About 0.2g of the sample of brass was weighed accurately and transferred into a clean dry 250ml beaker. To
this about 10ml of con. Nitric acid was added and allowed to boil for a small interval of time till the alloy was dissolved.
This was cooled, diluted with water and made upto 250 ml in a standard flask.

TITRATION I
STANDARDIZATION OF Na2S2O3 WITH K2Cr2O7 SOLUTION
20ml of the standard potassium dichromate solution is pipetted out into a conical flask. 20ml of dil.sulphuric
acid and 10ml of 10% KI are added. The liberated iodine is titrated against sodium thio sulphate taken in the burette till
the colour changes to yellowish green. 1ml of starch is added till the colour changes from blue to light green colour.
Titration is repeated for concordance.
44



CALCULATION


Amount of copper in 1lt of given brass solution = Strength of solution x Eq. Wt of Cu


= ------------------ N x 63.5

= -------------------------

So, Amount of copper in 100ml of given brass solution = ------------------- N x 63.5 x 100 / 1000



ie, ------------g of brass contains = -------------------- g of copper


therefore, % of copper in the given brass sample = ------------------- g x 100


= ------------------ g of brass


= ------------------------ %























45


TITRATION II

ESTIMATION OF COPPER

The brass solution is transferred into the 100ml standard flask and 10ml of dil. sulphuric acid is added and
made up to the mark using distilled water.

20ml of the alloy solutionis pipetted out into a conical flask. To this aqueous ammonia is added in drops till
a blue precipitate of Cu(OH) 2 is formed. One or two drops of acetic acid is added to dissolve the precipitate. To
this 10ml of 10% KI is added and titrated against standard thio sulphate using starch as indicator. The end point is
the disappearance of blue colour and appearance of green colour.



RESULT

The given sample of brass was found to contain copper = ------------- %





VIVA-VOCE



1. What is the composition of brass?
2. What is meant by iodometry?
3. What is the principle used in t his method?
4. What is the role of K 2Cr 2O 7?
5. What is the colour change in this titration?
6. Write the chemical reactions involved in this experiments?
7. How will you find out % of copper in brass?
8. What is the role of indicator?
9. What is the equivalent weight of copper?
10. What is the role of adding aqueous ammonia?


46


SHORT PROCEDURE
Standard solutions are prepared by the dilution of the given stock solution. The flasks are numbered and
the solutions are prepared according to the following table using different glass pipettes.



Flask number

1 2 3 4 5 6
Vol. of pipette to use 1 1 2 10 10 10
Vol. of Na stock solution to pipette 0.5 1 2 4 6 8
Conc. of solution obtained (?g/ml) 5 10 10 40 60 80



MODEL GRAPH








ABSORBANCE






CONCENTRATION








47

Expt. No 9 ESTIMATION OF SODIUM BY USING
FLAME PHOTOMETER
AIM
To estimate the amount of sodium present in whole of the given solution.

APPARATUS REQUIRED
1. Flame photometer FLAPHO or Eppendorf.
2. Stock solutions of Na+ and K+, C = 1 mg/ml.
3. 6 numbered 100 ml volumetric flasks.
4. Glass pipettes: 1, 2, 10 ml.

MEASUREMENT PROCEDURE

1. The flame photo meter is switched on.
2. The instrument is kept for warming.
3. Distilled water is fed into the instrument.
4. The element Na is selected by turning the selector ?Elementwahl?.
5. The outer knob ?Messbereich? is turned into position ?100?. The ?Kompensaton I? knob is pulled slightly
out and adjusted to 0. The ?Kompensation I? knob is pressed back. 0 reading is adjusted with
?Kompensation II? if necessary.
6. The most concentrated standard solution (solution number 6) is aspirated and is adjusted to 350 (on
uppermost scale) using inner ?Messbereich? knob.
6. Distilled water is aspirated till instrument reads 0.
7. The standard solutions no. 1, 2, 3, test solution, and then standards 4, 5, 6 are aspirated.
The results are recorded.
8. Distilled water is aspirated for at least 5 minutes to clean the system(FLAPHO flame photometer).
(FLAPHO is a dual channel instrument, which measures concentrations of Na simultaneously).







48



TABULATION


Flask No.

Concentration

Absorbance

1


2


3


4


5


6

Unknown Solution
X




















49




CALCULATION

1. The calibration curves are drawn for sodium and potassium on a sheet of millimeter-
paper. The concentrations are used as abscissa and instrument readouts as ordinate
values.
2. The concentration of sodium and potassium ions in test solution are found from
calibration curves.

RESULT

The amount of sodium present in whole of the given solution = ------------- g


VIVA - VOCE

1. What is meant by flame photometry?
2. How will you prepare blank solution?
3. Define ? Absorbance
4. State Beer ? Lamberts law.
5. What is the absorbance of sodium?
6. How will you find out unknown concentration of solution?
7. What is meant by wavelength?
8. How will you calibrate the instrument?
9. What is meant by flame emission spectroscopy?
10. Distinguish between absorption and emission spectrum.






50

LIST OF PROJECTS
1. Photo catalysis and water purification and electricity generation
2. The effect of acid rain on marigold plants
3. Using microorganisms (green algae) to bioremediate a source of waste water.
4. The effect of water hardness on the germination of marigold seeds
5. Turn milk into plastic!
6. Find out which household organic waste produce more biogas
7. What makes food decay faster?
8. Obesity: how greasy are your potato chips?
9. The effects of ph level on apple juice fermentation
10. Why does organic milk last so much longer than regular milk? [
11. How sugar content changes in ripening fruit
12. Do oranges lose or gain vitamin c after being picked?
13. Measuring glucose in your food
14. Determine if turmeric can prevent the growth of bacteria which cause foodborne illnesses.
15. What is the effect of antioxidants (vitamins a, e, c) on cells?
16. Will antioxidant supplements help you live longer?
17. Can cloning make a better plant?
18. Biotechnology in the food industry
19. Build a simple burglar alarm
20. Build and demonstrate a homemade fuel cell.
21. Demonstrate the energy stored inside a peanut
22. Increasing the useful lifetime of solar panels
23. The effect of fertilizers on algal growth
24. Determine the effects of neem tree extracts as antibacterial and antifungal agents as well as a pesticidal
agent.
25. Compare short term memory according to gender and age.
26. Which recipe will create the biggest bubbles?
27. Do twins have identical or similar fingerprints?
28. How do plants grow in different environments?
29. Reusable water-powered battery
30. Build a solar toy car and explain its operation.
31. Demonstrate the greenhouse effect in a jar.
51

32. Study the toxicity of energy drinks.
33. Formulate a non-toxic or biodegradable ink.
34. Compare fruits for their sugar content.
35. Using solar energy to purify polluted or salt water
36. Test for the amylase enzyme in your saliva
37. The effects fat has on freezing milk
38. How vehicles affect the ph properties of snow
39. Is radiation level elevated nearby our school?
40. Examines the levels of harmful bacteria that grow in baby food after it has been opened and used in both
refrigerated and room temperature environments.


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