Download VTU B-Tech/B.E 2019 June-July 1st And 2nd Semester 2014 June-July 10CHE12 Engineering Chemistry Question Paper

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College of Engg. & Tec

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10CHE12/22

First/Second Semester B.E. Degree Examination, June / July 2014

Engineering Chemistry

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Time: 3 hrs.

Max. Marks:100

Note: 1. Answer any FIVE full questions, choosing at least two from each part.

2. Answer all objective type questions only on OMR sheet page 5 of the answer booklet.

3. Answer to objective type questions on sheets other than OMR will not be valued.

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PART — A

1 a. Choose the correct answers for the following : (04 Marks)

1. Calomel electrode is reversible with respect to,
   A) H⁺ ion
   B) Ag⁺ ion
   

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   C) Hg⁺ ion
   D) None of these
2. A galvanic cell converts:
   A) Electrical energy in to chemical energy
   B) Chemical energy in to electrical energy
   

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   C) Electrical energy in to heat energy
   D) None of these
3. The E⁰ value of the cell Zn/Zn⁺//Fe²⁺/Fe is if E⁰_Fe²⁺/Fe = -0.44 and E⁰_Zn²⁺/Zn = -0.76
   A) +0.32 V
   B)+1.2 V
   

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   C) — 0.32V
   D) -1.2V
4. Example of an ion selective electrode is/
   A) Calomel electrode
   B) Hydrogen electrode
   

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   C) Platinum electrode
   D) Glass electrode

b. What are reference electrodes? Explain the construction and working of Calomel electrode (05 Marks)

c. What is single electrode potential? Obtain an expression for the same. (06 Marks)

d. An electrochemical cell is constructed by immersing a silver wire in AgNO₃ solution of 0.5 M and a Cadmium wire in CdSO₄ solution of 0.25 M at 25°C. Write the cell diagram, cell reaction and calculate emf of the cell and change in free energy. Given E⁰_Ag⁺ = +0.80 and E⁰_Cd²⁺= -0.40 F = 96.5 KJ/V (05 Marks)

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2 a. Choose the correct answers for the following : (04 Marks)

1. The density of H₂SO₄ to be maintained in the lead-acid storage cell is,
   A) 0.5
   B) 1.2
   C) 2.4
   

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   D) None of these
2. In which battery a key component is separated from rest of the battery prior to activation.
   A) Primary
   B) Secondary
   C) Reserve
   

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   D) None of these
3. The reaction taking place at anode of a battery,
   A) Reduction
   B) Addition
   C) Neutralization
   

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   D) Oxidation
4. The electrolyte used in H₂ — 0₂ fuel cell is,
   A) KOH
   B) NaCl
   C) NH₄OH
   

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   D) KCl

b. Explain the following battery characteristics: (06 Marks)

1. Voltage
2. Energy storage density
3. Cycle life

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c. Explain the construction and working of Ni — Cd battery. (06 Marks)

d. Explain the construction and working of H₂ — 0₂ fuel cell and mention its applications. (04 Marks)

3 a. Choose the correct answers for the following : (04 Marks)

1. Development of non porous and uniform oxide film over a metal surface due to corrosion,
   A) Decreases the corrosion rate
   

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   B) Increases the corrosion rate
   C) Does not have any effect
   D) None of these
2. Galvanizing is the process of coating of iron,
   A) With Au
   

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   B) With Zn
   C) With Cu
   D) None of these
3. Which of the following is an example of cathodic coating,
   A) Galvanizing
   

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   B) Tinning
   C) Painting
   D) None of these
4. Evolution of hydrogen type of corrosion occurs in,
   A) Acidic medium
   

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   B) Basic medium
   C) Both a and b
   D) None of these

b. What is metallic corrosion? Explain the electro chemical theory of corrosion, (05 Marks)

c. Discuss the effect of the following factors on corrosion rate: (06 Marks)

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1. Nature of oxide film
2. Anodic to cathodic area
3. Polarization

d. Explain the corrosion control methods: (05 Marks)

1. Use of inhibitor

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2. Galvanisation

4 a. Choose the correct answers for the following : (04 Marks)

1. Technological importance of metal finishing is to impart,
   A) Corrosion resistance
   B) Solderability
   

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   C) Thermal resistance
   D) All of these
2. Use of complexing agent during electrode-deposition is to,
   A) Obtain shining deposit
   B) To check the metal ion concentration
   

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   C) Increase current density
   D) None of these
3. The process used to manufacture P.C.B is,
   A) Electroplating
   B) Electroless plating
   

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   C) Phosphating
   D) None of these
4. Electroless plating process Is Possible only on,
   A) Catalytically active surface
   B) Inactive surface
   

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   C) Any surface
   D) Only on plastic surface

b. What is metal finishing? Mention any 3 technological importance of metal finishing. (06 Marks)

c. Explain the factors that influence the nature of electrodeposit, (04 Marks)

1. pH of electrolytic bath

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2. temperature
3. current density

d. What is electroless plating? Explain the process of electroless plating of copper. (06 Marks)

PART — ?

5 a. Choose the correct answers for the following: (04 Marks)

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1. Methyl tertiary butyl ether is added to gasoline to,
   A) To increase the cetane number
   B) Minimize the knocking
   C) To increase the efficiency of diesel
   D) All of these

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2. Which of the following posses zero octane number,
   A) Iso Octane
   B) a-Methyl naphthalene
   C) n-heptane
   D) Cyclohexane

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3. Photovoltaic cell is a,
   A) Storage cell
   B) Rechargeable cell
   C) Fuel cell
   D) Energy conversion device

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4. Knocking is due to,
   A) Slow combustion
   B) Incomplete combustion
   C) Instantaneous explosive combustion
   D) All of these

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b. What is calorific value of a fuel? Explain the bomb calorimeter method to determine calorific value of a solid fuel. (06 Marks)

c. Calculate the gross and net calorific value of a coal sample from the following data: (05 Marks)

1. Weight of coal - 0.73 g
2. Weight of water taken in calorimeter 1500 g
3. Water equivalent of calorimeter = 470 g

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4. Rise in temperature 2.3°C
5. Percentage of hydrogen in coal sample 2.5%
6. Latent heat of steam is 587 cal/g^-1

d. Explain the methods of doping of silicon to get solar grade silicon. (05 Marks)

6 a. Choose the correct answers for the following : (04 Marks)

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1. Gibbs phase rule for general system:
   A) P + I = C-2
   B) P + F = C-1
   C) P + F = C+1
   D) P + F = C+2

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2. Which of the following is a one component system,
   A) Water system
   B) Lead - Silver system
   C) Iron - Carbon system
   D) None of these

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3. Absorbance of light by a solution of a substance depends on,
   A) Path length
   B) Concentration of solution
   C) Wavelength of incident light
   D) All of these

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4. Flame photometry is suitable for the detection of,
   A) Li
   B) Cu
   C) Fe
   D) Zn

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b. State phase rule. Discuss the application of phase rule to water system. (05 Marks)

c. Explain the principle and application of potentiometric titration with respect to redox titration. (06 Marks)

d. Discuss the conductometric titration and mention the advantages. (05 Marks)

7 a. Choose the correct answers for the following : (04 Marks)

1. Which of the following is a co polymer?
   

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   A) Polythene
   B) Nitrile rubber
   C) PVC
   D) Plexi glass
2. Requirement for conductivity polymer is,
   

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   A) Linear structure
   B) Presence of oxidising or reducing agents
   C) Conjugation
   D) None of these
3. Natural rubber is polymerized form of,
   

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   A) Chloroperene
   B) Isoprene
   C) Propene
   D) None of these
4. Benzoyl peroxide is used as,
   

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   A) Initiator
   B) Terminator
   C) Propogator
   D) All of these

b. What is polymerization? Explain the addition polymerization's mechanism by taking poly ethylene as example. (05 Marks)

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c. Explain the mechanism of conduction in poly acetylene. (05 Marks)

d. Explain the manufacture of following polymers and mention the uses: (06 Marks)

1. Poly Methyl methacrylate.
2. Neoperene.

8 a. Choose the correct answers for the following : (04 Marks)

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1. Alkalinity in water is not due to,
   A) H⁺
   B) OH^-
   C) CO₃^2-
   D) HCO₃^-

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2. The titrant used in estimation of total hardness of water is,
   A) EDTA
   B) E.B.T
   C) NaCl
   D) KOH

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3. The reagent used in the estimation of sulphate ion in water is,
   A) Phenoldisulfonic acid
   B) SPANDS
   C) Ammonia
   D) Barium Chloride

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4. Temporary hardness of water is due to,
   A) Ca(HCO₃)₂
   B) CaCl₂
   C) CaSO₄
   D) MgSO₄

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b. What is desalination of water? Explain electrodialysis method. (05 Marks)

c. Explain the experimental method of determination of total hardness of water. (06 Marks)

d. 50 ml of sample of water consumed 15 ml of 0.01 M EDTA, before boiling and 5 ml of the same EDTA, after boiling. Calculate the total hardness, permanent hardness and temporary hardness. (05 Marks)