DEPARTMENT OF SCIENCE AND HUMANITIES
I SEMESTER - R 2017
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BS8161 CHEMISTRY LABORATORY
LABORATORY MANUAL
Name : _________________________
Register No : _________________________
Section : _________________________
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VISION
College of Engineering is committed to provide highly disciplined, conscientious and enterprising professionals conforming to global standards through value based quality education and training.
MISSION
- 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
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PROGRAMME EDUCATIONAL OBJECTIVES (PEOS)
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- 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
- 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
- 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
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- 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
- 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
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PROGRAMME OUTCOMES (POS)
To demonstrate and apply knowledge of Mathematics, Science and engineering fundamentals in the following experiments.
- To estimate HCI using Na2CO3 as primary standard and Determination of alkalinity in water sample.
- To determine total, temporary & permanent hardness of water by EDTA method.
- To determine DO content of water sample by Winkler's method.
- To determine chloride content of water sample by Argentometric method.
- To estimate copper content of the given solution by Iodometry.
- To determine strength of given hydrochloric acid using pH meter.
- To determine strength of acids in a mixture of acids using conductivity meter.
- To determine iron content of the given solution using potentiometer.
- To estimate iron content of the water sample using spectrophotometer (1, 10- Phenanthroline / thiocyanate method).
- To estimate sodium and potassium present in water using flame photometer.
- To determine molecular weight of polyvinyl alcohol using Ostwald viscometer.
- To determine Pseudo first order kinetics –ester hydrolysis.
- To determine Corrosion experiment-weight loss method.
- To estimate CMC.
- To estimate Phase change in a solid.
- To determine strength of strong acid vs strong base using conductivity meter.
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BS8161-CHEMISTRY LABORATORY SYLLABUS
COURSE OBJECTIVES
- 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.
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LIST OF EXPERIMENTS:
- Estimation of HCl using Na2CO3 as primary standard and Determination of alkalinity in water sample.
- Determination of total, temporary & permanent hardness of water by EDTA method.
- Determination of DO content of water sample by Winkler's method.
- Determination of chloride content of water sample by Argentometric method.
- Estimation of copper content of the given solution by lodometry.
- Determination of strength of given hydrochloric acid using pH meter.
- Determination of strength of acids in a mixture of acids using conductivity meter.
- Estimation of iron content of the given solution using potentiometer.
- Estimation of iron content of the water sample using spectrophotometer (1, 10-Phenanthroline / thiocyanate method)
- Estimation of sodium and potassium present in water using flame photometer.
- Determination of molecular weight of polyvinyl alcohol using Ostwald viscometer.
- Pseudo first order kinetics –ester hydrolysis.
- Corrosion experiment -weight loss method.
- Determination of CMC.
- Phase change in a solid.
- Conductometric titration of strong acid vs strong base.
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COURSE OUTCOMES
- The students will be outfitted with hands-on knowledge in the quantitative chemical analysis of water quality related parameters.
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INDEX [SEMESTER-1]
| S.No. | Date | Experiment | Date of submission | Mark | Signature |
|---|---|---|---|---|---|
| 1. | Estimation of HCI using Na2CO3 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 lodometry | ||||
| 9. | Estimation of sodium and potassium present in water using flame photometer |
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CONTENTS
| S.No. | NAME OF EXPERIMENT | PAGE No. |
|---|---|---|
| SEMESTER - I | ||
| 1. | Estimation of HCl using Na2CO3 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 |
| 8 | Estimation of copper content of the given solution by lodometry | 43 |
| 9 | Estimation of sodium and potassium present in water using flame photometer | 47 |
SHORT PROCEDURE:
| CONTENTS | TITRATION |
|---|---|
| Estimation of alkalinity in water sample --- Content provided by FirstRanker.com --- (Std HCI Vs water sample) | |
| Burette solution | Std. HCI |
| 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 | HCO3 | CO32- |
|---|---|---|---|---|---|
| P = M | only OH | P or M | - | 0.0 | 0.0 |
| 2P = M | only CO32- | 2P or M | 0.0 | 0.0 | - |
| P =0, M?0 | only HCO3 | M | 0.0 | - | 0.0 |
| 2P > M | OH &CO32 | OH = 2P-M CO32 = 2(M-P) | - | 0.0 | - |
| P< 1½ M | HCO3 &CO32 | HCO3 = M-2P CO32 = 2P | 0.0 | - | - |
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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 Na2CO3 of strength _N is given.
PRINCIPLE
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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 HCI 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+ ? H2O completed at pH 8.2-9.0 (1)
CO32- + H+ ? HCO3 (2)
HCO3 + H+ ? (H2CO3) ? H2O + CO2, completed at pH 4.2-5.5 (3)
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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 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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Titration
Estimation of Alkalinity in water sample
Standard HCI Vs Water sample Indicator: 1. Phenolphthalein 2. Methyl Orange
| S.No. | Volume of water sample (ml) | Initial | Phenolphthalein End Point (P) | Methyl Orange End Point (M) | Concordant value |
|---|---|---|---|---|---|
| 1 | |||||
| 2 |
CALCULATION
Hydroxide ion alkalinity
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Volume of HCI (2P-M) = .ml
Strength of HCI = N
Volume of water sample = ml
Strength of water sample = Volume of HCI (2P-M) X Strength of HCI
Volume of water sample
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• Hydroxide ion alkalinity in terms of
CaCO3 equivalent = Strength of water sample X Equivalent weight of CaCO3 X 1000
= Strength of water sample x 50 x 1000
= .mg/l
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- From the magnitudes of the P & M, the nature of alkalinity can be arrived as follows:
- P = M => Presence of only OH
- 2P = M => Presence of only CO32-
- P =0, M=0 => Presence of only HCO3
- 2P > M => Presence of OH & CO32-
- 2P < M => Presence of HCO3¯ & CO32-
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(Mixture of OH & HCO3 is not listed since they do not exist together and are considered equivalent to CO32).
PROCEDURE
TITRATION
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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.
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Carbonate ion alkalinity
Volume of HCI 2 (M –P) = .ml
Strength of HCI = .N
Volume of water sample = .ml
Strength of water sample = Volume of HCI 2 (M –P) X Strength of HCI
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Volume of water sample
= N
Carbonate ion alkalinity
in terms of CaCO3equivalent = Strength of water sample X Equivalent weight of CaCO3 X 1000
= Strength of water sample x 50 x 1000
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= .mg/l
RESULT
- The type of alkalinity present in the water sample = ----ions.
- The individual amounts of alkalinity present in the water sample:
Hydroxide ion alkalinity = ppm
Carbonate ion alkalinity = ppm
Bicarbonate ion alkalinity = ppm
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VIVA-VOCE
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- What is meant by alkalinity?
- What are the ions responsible for alkalinity?
- Why OH and HCO3¯ions cannot exist together in water?
- What are the ions responsible for alkalinity when 2P > M?
- What is the pH range for both acidic and basic solutions?
- What is the colour of phenolphthalein in an acid and in an alkaline solution?
- What is the purpose of using two indicators in same titration?
- What are the possible combinations of ions for alkalinity?
- How is the amount of alkalinity expressed?
- What are the types of indicator used in this experiment?
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SHORT PROCEDURE
| CONTENTS | TITRATION I Standardisation of EDTA (EDTA Vs Std Hard water) | TITRATION II Determination of total hardness (Std EDTA Vs Hard water sample) | TITRATION III 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 - I1
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Std. HARD WATER VS EDTA Indicator: EBT
| S. No. | Volume of std hard water (ml) | Initial | Final | Volume of EDTA (V1) (ml) | Concordant value |
|---|---|---|---|---|---|
Volume of std.hard water taken = 20 ml
Volume of EDTA consumed (V1) = ml
1 ml of std.hard water = 1mg of CaCO3
20 ml of std hard water = 20 mg of CaCO3
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V1 ml of EDTA solution containing 20 mg of CaCO3
1 ml of EDTA solution = 20 / V1 mg of CaCO3
---------mg of CaCO3
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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.
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- 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.
- Temporary hardness is removed by boiling the water
Ca (HCO3)2 ? CaCO3 + CO2 ?+H2O
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Mg (HCO3)2 ? Mg(OH)2 +2CO2 ?
The precipitate is filtered and the remaining permanent hardness is estimated using EDTA.
PROCEDURE
TITRATION - 1
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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 V1ml.
Titration-II
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SAMPLE HARD WATER Vs Std EDTA Indicator: EBT
| S.No. | Volume of sample hard water (ml) | Initial | Final | Volume of EDTA (V2) (ml) | Concordant value |
|---|---|---|---|---|---|
CALCULATION
Calculation of total hardness
Volume of EDTA consumed (V2) = ml
1ml of EDTA = 20 / V1 mg of CaCO3
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V2 ml of EDTA = 20/V1x V2 mg of CaCO3
(i.e), If 20ml of sample hard water contains 20 x mg of CaCO3 / V1
Then 1000ml of water sample = 20 x V2 x 1000 / V1x 20 mg of CaCO3
= 1000 x V2/ V1 mg of CaCO3
Total hardness of given water sample = --------------ppm
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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 V2ml.
DETERMINATION OF PERMANENT HARDNESS
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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 V3ml. Temporary hardness is calculated by subtracting permanent hardness from total hardness.
DETERMINATION OF PERMANENT HARDNESS
BOILED SAMPLE WATER Vs Std. EDTA Indicator: EBT
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| S.No. | Volume of boiled hard water (ml) | Initial | Final | Volume of EDTA (ml) | Concordant value |
|---|---|---|---|---|---|
CALCULATION OF PERMANENT HARDNESS
Volume of EDTA consumed V3 = ml
1ml of EDTA = 20 / V1 mg of CaCO3
V3ml of EDTA = 20 / V1 x V3 mg of CaCO3
(i.e) 20 ml of boiled sample hard water = 20 / V1 x V3 mg of CaCO3
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Then 1000ml of boiled water sample = 20 / V1x V3 / 20 * 1000mg of CaCO3
= 1000 x V3/ V1 mg of CaCO3
permanent hardness of boiled water sample = -ppm
Temporary hardness of the given water sample = Total hardness - Permanent hardness
-ppm
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RESULT
- Total hardness of the given sample water = ppm.
- Permanent hardness of the given sample water = ppm.
- Temporary hardness of the given sample water -ppm.
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VIVA-VOCE
- Define - Hard water
- What is the structure of EDTA?
- How will you calculate temporary hardness?
- What is the role of the buffer in EDTA titration?
- What is the permissible limit of hardness in drinking water?
- Name the hardness producing ions present in water.
- Name two salts which are responsible for temporary hardness.
- Why is CaCO3 taken as the standard?
- Write the expansion of EDTA.
- What is meant by EBT?
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SHORT PROCEDURE
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| CONTENTS |
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