VTU Question Papers Engineering Chemistry June July 2009

VTU Question Papers Engineering Chemistry

1st & 2nd Sem B.E. Degree Examination, June-July 2009

 

Note: 1. Answer any Five full question, choosing at least two from each part

  1. Answer all objectives type questions only in OMR sheet page 5 of the Answer Booklet
  2. Answer to the objective type questions on sheets other than OMR will not be valued.

PART-A

1        a. i) The tendency of knocking is high in

A) Aromatics                                      B) Olefins

C) Straight chain hychocarbons D) Cycloparaffins.

ii)          A device in which electricity is produced using solar energy is called A) Fuel ceil  B) Voltaic cell

C) Photovoltaic cell                          D) Concentration ceil.

iii)        Knocking is due to

A) Slow Combustion                          B) Instantaneous explosive combustion

C) Incomplete combustion               D) All

iv)        Which of the following is a primary fuel

A) Producer gas                                  B) Coal gas

C) Petroleum #                                     D) Water gas.                                      (04 Marks)

  1. What is cracking? Explain fluidised bed catalytic cracking.                             (06 Marks)
  2. Give the construction and working of photovoltaic cell.                                   (05 Marks)
    1. Calculate the gross and net calorific value of a sample of coke from the following data.

Mass of coke = 0.795 x 10~ kg

Water equivalent of calorimeter = 2.5 kg.

Mass of water = 1.3 kg.

Specific heat of water = 4.187 KJ kg’1 K’1 Rise in temperature = 1.8 K.

% hydrogen in the fuel sample — 2.5, Latent heat – 587 Cal/g.                        (05 Marks)

3          a. i) The fuel cells are more superior than the conventional batteries because

A) They are light in weight                           B) They are eco-friendly

C) They produce direct current at low cost D) They are easily fabricated.

ii)          The electrolyte used in Zn-Air batteiy is

A) Aqueous sulphuric acid                            B) Aquious potassium hydroxide

C) Concentrated potassium chloride            D) None of these.

iii)        Which of the following is a reserve battery

A) Zn-Air                                                         B) Ni-MH

C) Zn-A&O                                                      D) Li-Mn02

iv)        In lead acid batteiy, during discharge the product formed at the electrodes is A) Pb02                                                                   B) PbO

C) PbSo4                                                            D) Pb                                       (04 Marks)

  1. Explain the following characteristics of a battery

i)             Capacity ii) Energy density                     iii) Cycle life.                              (06 Marks)

  1. Explain construction, working and applications of Ni-Cd batteiy.                   (05 Marks)
  2. Explain the construction and working of methanol – oxygen fuel cell.            (05 Marks)

4          a. i) Coating used for the iron container used for food package coated with

A) . Zinc                                                         B)Tin

C) Lead                                                          D) Aluminium

ii)          Water line corrosion in steel tank is an example

A) Differential metal corrosion                 B) Pitting corrosion

C) Differential aeration corrosion            D) Stress corrosion

iii)        Caustic embrittlement in the boiler is an example of

A) Stress corrosion                                      B) Pitting corrosion

C) Water line corrosion                              D) Differential metal corrosion

iv)        Sacrificial anode method of protecting a metal is an example of A) Anodic protection                                                     B) Cathodic protection

C) Metal coating                                          D) Organic coating                   (04 Marks)

  1. Define metallic corrosion. Discuss the following factors which affect the rate of corrosion

i)             Relative areas of anode and cathode ii) pH of the medium.                     (06 Marks)

  1. What is cathodic protection? Explain cathodic protection by impressed current technique.

(04 Marks)

d Define corrosion inhibition. Explain anodic and cathodic inhibition, anodic inhibitors with suitable example.                                                                                                      (06 Marks)

PART-B

5          a. i) In the electro plating process, the over voltage potential depends on

A) Electrolyte                                               B) Temperature

C) Current density                                       D) All of these

ii)          In chromium plating, anode is

A) Soluble chromium anodes                    B) Insoluble anodes

C) Inert anodes                                             D) Both B and C

iii)        Auto catalytic reduction method of plating is also known as

A) Electroplating                                         B) Electrolysis plating

C) Electro less plating                                 D) Electro refining

iv)        For a, electrolytic mixture containing Zn**, Cu1^, Ag+ the ion which is going to be discharged first is

A) Zn*                                                           B) CuM

C) Ag+                                                            D) None                                                    (04 Marks)

  1. Explain decomposition potential and over voltage. Why practical decomposition potential is greater than theoretical decomposition potential.                                               (05 Marks)
  2. Explain electroplating of Nickel. Give the applications.                                    (05 Marks)
  3. Explain electro less plating of copper.                                                                                                              (06 Maries)

6         a. i) P-azoxy anisole is

A) Smectic                                          B) Nematic

C) Cholasteric                                    D) None

ii)          The mesophases which are formed by heating and cooling cycle are called A) Monotropic phases                           B) Enantiotropic phases

C) Lyotropic phases                          D) Thermotropic phases.

iii)        In the estimation of FAS by potentiometry the indictor electrode used is A) Silver-silver chloride electrode B) Platinum electrode

C) Calomelelectrode                         D) Glass electrode.

iv)        Measurement of optical density using monochromatic light in colorimetry involves A) IR range                                              B) Visible range

C) UV range                                       D) All the above.                                 (04 Marks)

  1. Distinguish between thermotropic and lyotropic liquid crystals. Give examples. (04 Marks)
    1. What is homologuous series? Explain the liquid crystalline behavior homolog of PAA.

(06 Marks)

State Lambert’s Law and Beer’s law. Explain the colorimetric estimation of copper using NHj as the complexing agent.        (06 Marks)

7         a. i) A polymer with higher Tg value is

A) PVC                   B) Poly ethylene C) Poly propylene D) Poly styrene.

ii)           The monomer tetrofluro ethylene can be used for the preparation of

A) PMMA B) Polyurethane C) Teflon                                D) Polyethylene.

iii)       The polymer which can be used as synthetic adhesive is

A) Neoprene B) Buna s                         C) Epoxy resin D) Polystyrene.

iv)        Co-polymer of Isoprear and butadiene is known as

A) Butyl rubber B) Buna s                    C) PTFE                 D) Polyurethane.

(G4 Marks)

5                                                                                                                                                                                                                                                                                  Explain addition and condensation polymerization with examples.                                                                                                         (06 Marks)

c Give the synthesis and uses of i) Epoxy resin ii) Neoprene.                                                                                (06 Marks)

{j. What is glass transition temperature? Explain any two factors that affect glass transition temperature.           (04 Marks)

 

2     a. i) In a concentration cell, the electrode kept is contact with a solution of lower

concentration acts as

A) Anode                                            B) Cathode

C) Both anode and cathode               D) None

ii)          Example of an ion-selective electrode is

A) Calomel electrode                       B) Platinum electrode

C) Glass-electrode                           D) Ag-Agcl electrode.

iii)        Calomel electrode is reversible with respect to A) Mercuric ion                                     B) Mercury C) Chloride ion D) Platinum

iv)        In a galvanic cell, the oxidation takes place at:

A) Cathode                                       B) Anode

C) Electrolyte                                   D) Salt bridge.                                      (04 Marks)

  1. What are secondary reference electrodes? Explain construction and working of Calomel electrode.                                                                                                                   (06 Marks)
  2. Explain determination of pH using glass electrode.                                            (05 Marks)

8     a. i) Permanent hardness of water is caused due to the presence of

A) CaCo3 B) Ca (HC03)2 C) CacI2                                    D)A11

ii)          Winkler methods is used to determine

A) COD B) BOD                        C) Dissolved oxygen D) Both B and C

iii)        Which of the following alkalinity is not present in water is

, 2 — —

A) C03 a HC03                        B)C03_a0H

C) OH only                                    D)HC03and0H

iv)        The method used for desalination of water is

A) Lime soda proccss                  B) Reverse osmosis

C) Ion-exchange process             D)Permutit process.                                (04 Marks)

  1. Explain the determination of permanent and temporary hardier of water by EDTA method.

(06 Marks)

  1. Explain gravimetric method of determination of sulfate content in water.     (OS Marks)
  2. Explain destination of water reverse osmosis.                                                     (05 Marks)

3  of 3

  1. What are reference electrodes? Explain construction and working of Ag-Agcl electrode.

(05 Marks)

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