Engineering Chemistry - Dec 2011

First Year Engineering (C Cycle) (Semester 2)

TOTAL MARKS: 100
TOTAL TIME: 3 HOURS (1) Question 1 is compulsory.
(2) Attempt any four from the remaining questions.
(3) Assume data wherever required.
(4) Figures to the right indicate full marks.

Choose your answer for the following :-

1 (a) (i) The reference electrode used in measurement of standard reduction potential is
(A) Standard calomel electrode
(B) Hydrogen electrode
(C) Ag-Agel electrode
(D) Standard hydrogen electrode(1 marks) 1 (a) (ii) When the concetration of chloride ions in Ag-Agel electrode increases, the potential of the electrode
(A) Increases
(B) Decreases
(C) Does not change
(D) None of these(1 marks) 1 (a) (iii) Nernsts equation is based on
(A) Thermodynamic principle
(B) An equation for redox potential
(C) Increase in the free energy of the system
(D) None of the above(1 marks) 1 (a) (iv) In a Galvanic cell oxidation takes place at
(A) Electrolyte
(B) Cathode
(C) Anode
(D) Salt bridge(1 marks) 1 (b) What are concentration cells ? Derive an expression for the EMF of a concentartion cell.(5 marks) 1 (c) Define standard electrode potential. Explain the origin of electrode potential.(6 marks) 1 (d) An electro chemical cell if formed from nickel and lead electrodes having 0.01m NiSO₄ and 0.5m PbSO₄ Electrolytes. The standard electrode potentials of Ni and Pb electrodes are -0.24V and -0.13V respectively. Write the cell scheme, cell reaction and calculate EMF of the cell at 298 K.(5 marks)

Choose your answer for the following :-

2 (a) (i) Cycle life is applicable only to
(A) Primary batteries
(B) Secondary batteries
(C) Reserve batteries
(D) All the above(1 marks) 2 (a) (ii) The electrolyte used in z_n-air battery is
(A) aq H₂SO₄
(B) Conc.KC/
(C) Aq.KOH
(D) Aq.Hc/(1 marks) 2 (a) (iii) EMF of a battery depends on
(A) Standard electrode potential
(B) Temperature
(C) Reaction quotient
(D) All the above(1 marks) 2 (a) (iv) The fuel cells are more superior than the batteries as
(A) They are light in weight
(B) They are eco friendly
(C) They produce current at low cost
(D) All the above(1 marks) 2 (b) Discuss construction and working of load-acid storage battery.(6 marks) 2 (c) Explain construction and working Ni-MH battery.(4 marks) 2 (d) What are fuel cells? Describe the construction and working of CH₃OH-O₂ fuel cell.(6 marks)

Choose your answer for the following :-

3 (a) (i) At high hydrogen over voltage, the rate of corrosion
(A) Increases
(B) Decreases
(C) Increases initially and then decreases
(D) Remains un changed(1 marks) 3 (a) (ii) Metal iron is coated with zinc metal to prevent corrosion. The process is
(A) Anodic coating
(B) Cathodic coating
(C) Inorganic coating
(D) painting(1 marks) 3 (a) (iii) In corrosion, the gas which is produced in acidic medium is
(A) Hydrogen
(B) Oxygen
(C) Nitrogen
(D) Carbon dioxide(1 marks) 3 (a) (iv) The type of corrosion occuring in wire frnce is
(A) Galvanic corrosion
(B) Inter-granular corrosion
(C) Differential aeration corrosion
(D) Water-line corrosion(1 marks) 3 (b) Discuss
(i) Stress corrosion
(ii) Water line corrosion(6 marks) 3 (c) Explain the influence of following factors on the rate if corrosion:
(i) Nature of corrosion product
(ii) Anodic and cathodic area(4 marks) 3 (d) Describe the following process : (i) Galvanising ; (ii) Tinning(6 marks)

Choose your answer for the following :-

4 (a) (i) In electroplatting, the article to be plated is subjected to picking, this is to
(A) Remove greses
(B) Increase rate of plating
(C) Remove oxide scale
(D) Get a bright deposite(1 marks) 4 (a) (ii) The decomposition potential is equal to
(A) Back EMF
(B) Cell voltage <be> (C) Current density
(D) None of the above</be>(1 marks) 4 (a) (iii) Brightners are added to plating bath in order to
(A) To get uniform deposite
(B) Make grain size of the deposite smaller thatn ? of light
(C) TO get thick deposit
(D) Remove colour(1 marks) 4 (a) (iv) Which of the following is essential in electroless plating
(A) Oxidising agent
(B) Reducing agent
(C) Anode
(D) Electrical energy(1 marks) 4 (b) What is meant by metal finishing? Explain the process of electroplating of gold.(6 marks) 4 (c) Discuss the influence of the following in electroplating bath solution.(4 marks) 4 (d) What is electroless plating ? Explain electroless plating of nickel, with relavent reactions.
(i) Complexing agent
(ii) wetting agent(6 marks)

Choose your answer for the following :-

5 (a) (i) The process of breaking down hydrocarbons of higher molecular weight into lighter hydrocarbons is known as
(A) Refining
(B) Reforming
(C) Isomerization
(D) Cracking(1 marks) 5 (a) (ii) The octane number of a fuel is a measure of
(A) Its ability to resist anti knocking
(B) Inability to offer resistance for knocking
(C) Its ability to resist knocking
(D) None of the above.(1 marks) 5 (a) (iii) The addition of TEL to gasoline is
(A) Decreases the octane number
(B) Increases the octane number
(C) Decreases the cetane number
(D) Increases the cetane number(1 marks) 5 (a) (iv) Photovoltaic cell consists of
(A) p-n junction
(B) n-type junction
(C) p-type junction
(D) None of the above(1 marks) 5 (b) What is reforming of petroleum ? Give any four reactions involved in reforming.(6 marks) 5 (c) Discuss the following : (i) Power alcohol ; (ii) Biodiesl(6 marks) 5 (d) On burning 0.85 × 10³¹ kg of a solid fuel in a bomb calorimeter, the temperaure of 2.1 kg water is raised from 24°C to 27.6°C. The water equivalent of calorimeter and latent heat of steam are 1.1 kg and 2454 kJ/kg repsectively. specific heat of water is 4.187 kJ/kg. If the fuel contains 2% hydrogen, calculate its gross and net calorific values.(4 marks)

Choose your answer for the following :-

6 (a) (i) Flame photometer is based on
(A) Atomic absorption
(B) Molecular absorption
(C) Atomic emission
(D) All the above(1 marks) 6 (a) (ii) Condensed phase rule for a two component system
(A) P+F=C+3
(B) P+F=C-2
(C) P+C=F+1
(D) P+F=C+1(1 marks) 6 (a) (iii) At eutectic point the composition of lead and silver has
(A) Lowest melting point
(B) Highest melting point
(C) Lowest boiling point
(D) Highest boiling point(1 marks) 6 (a) (iv) The filter used in copper colorimetry is
(A) 420 mm
(B) 520 mm
(C) 620 mm
(D) 320 mm(1 marks) 6 (b) State phase rule. Give phase diagram of water system and explain application of phase rule to water system.(6 marks) 6 (c) Explain the application of phase-rule to lead siler system.(6 marks) 6 (d) Given the components of the instruments required for potentiometry. Explain an application of potentiometry.(4 marks)

Choose your answer for the following :-

7 (a) (i) Kevlar is
(A) Polyurethane
(B) Polycarbonate
(C) Polystyrene
(D) Polyamide(1 marks) 7 (a) (ii) Which one is a conducting polymer?
(A) Aniline
(B) Pyrrole
(C) Poly acetylene
(D) Acetylene(1 marks) 7 (a) (iii) Very high molecular weight polymers will have
(A) Low Tg
(B) High Tg
(C) Moderate Tg
(D) No Tg(1 marks) 7 (a) (iv) The polymer widely used in making inner tubes of tyre is
(A) Neoprene rubber
(B) Butyl rubber
(C) Styru-butadiene rubber
(D) Natural rubber(1 marks) 7 (b) What are polymers? Discuss the free radical mechanism of polymerization of ethylene.(5 marks) 7 (c) Give the synthesis and an application of (i) Silicone rubber (ii) Teflon(6 marks) 7 (d) What are the deficiencies of natural rubber? Explain vulcanization of rubber.(5 marks)

Choose your answer for the following :-

8 (a) (i) Chloride content of water sample is determined by
(A) Colorimetric method
(B) Argentometric method
(C) SPADNS method
(D) gravimetric method(1 marks) 8 (a) (ii) As the temperature increases, the amount of dissolved oxygen of water sample
(A) Increases
(B) Decreases
(C) Has no effect
(D) None of the above(1 marks) 8 (a) (iii) Reverese osmosis is a method of getting pure water form
(A) Sewage water
(B) Industrial waste water
(C) Sea water
(D) River water(1 marks) 8 (a) (iv) Estimation of total hardness of water using EDTA titrant involves
(A) Neutralisation reaction
(B) Redox reaction
(C) Precipitation reaction
(D) Complexometric reaction(1 marks) 8 (b) How is alkalinity of water caused? Explain the method of determination of alkalinity.(6 marks) 8 (c) Describe electrodialysis method of desalination of water.(6 marks) 8 (d) 25 CC of waste water was mixed with 25 CC of k₂Cr₂O₇. Acidified and refluxed. The unreacted K₂ Cr₂O₇ required 8.2 CC of 0.2N FAS. In a blank titration 25 CC of K₂Cr₂O₇ acidified required 16.4 CC of same FAS. calculate COD of waste water.(4 marks)