183202 (CY2161) Engineering Chemistry II Second Semester B.E./B.Tech.Degree Examinations, November/December 2010 question paper


B.E./B.Tech.Degree Examinations, November/December 2010
Regulations 2008
Second Semester

Common to all branches (except Marine Engg)
CY2161 Engineering Chemistry II

Time: Three Hours Maximum: 100 Marks
Answer ALL Questions

Part A - (10 x 2 = 20 Marks)

1. What i s single electrode potential?
2. De¯ne a reference electrode with an example.
3. What i s the e®ect of H2S gas when it comes into contact with iron metal?
4. What are organic inhibitors? What will be the reason for the increase in inhibiting
power of aliphatic amines in the following given order? NH3 <
R3N.
5. With an example, state what is cracking.
6. Write the expression for the amount of air required for combustion of
1 kg fuel.
7. De¯ne the degrees of freedom in phase rule.
8. Mention any two advantages of alloy making.
9. What are chromophores? Give one example.
10. What is the principle of estimation of iron by colorimetry?

Part B - (5 x 16 = 80 Marks)

11. (a) (i) What is an ion selective electrode? Explain its principle and working. (6)
(ii) Derive an expression for Nernst equation. The emf of a cell measured by
means of a hydrogen electrode against a saturated calomel electrode at
298 K is 0.4188 V. If the pressure of the H2(g) was maintained at 1 atm,
calculate the pH of the unknown solution, given the potential of reference
calomel electrode i s 0.2415 V. (10)

OR

11. (b) Give a detailed account of conductometric titrations. (16)
12. (a) (i) Explain the sacri¯cial anode and impressed current techniques for the pre-
vention of corrosion. (8)
(ii) What are the factors which in°uence chemical corrosion and electrochem-
ical corrosion? (8)

OR

12. (b) (i) What are corrosion inhibitors? Classify di®erent types of inhibitors with
examples. (8)
(ii) What are the requisites of a good paint? Discuss the ingredients of a paint
and explain their functions. (8)
13. (a) (i) How i s metallurgical coke manufactured by Otto Ho®mann's method?
What are the important by products recovered from coke oven gas? (8)
(ii) Describe the signi¯cance of ultimate analysis of coal. (4)
(iii) List the fractions of hydrocarbons collected between boiling range of 30±C-
400±C by fractional distillation of crude oil.
(4)

OR

13. (b) (i) What i s hydrogenation of coal? Write the Fischer-Tropsh process of man-
ufacture of liquid fuels from solid fuels. (8)
(ii) Write in detail chemical reactions involved in the manufacture of producer
gas and mention its chemical composition. (8)
14. (a) (i) Illustrate with an example how phase diagrams are drawn from thermal
analysis data. (10)
(ii) Determine P and C and calculate F for the decomposition of CaCO3 in a
closed vessel.
CaCO3(s)  CaO(s) + CO2(g) (6)

OR

14. (b) (i) Mention two non-ferrous alloys. Give their composition and uses. (6)
(ii) Name ¯ve di®erent alloy steels and brie°y explain their applications. (10)
15. (a) (i) Write the principle of UV spectroscopy. (6)
(ii) Write the mechanism of interaction between the vibrating molecule and
infra-red radiation. (6)
(iii) A solution of thickness 2 cm. transmitted 40% incident light. Calculate
the concentration of this solution, given that the molar absorptivity is 6000
dm3 mol¡1cm¡1. (4)

OR

15. (b) (i) With a neat diagram explain the principle, instrumentation and working
of atomic absorption spectroscope. How will you estimate the amount of
nickel using atomic absorption spectroscopy? (10)
(ii) Describe the steps involved in the determination of sodium ion concentra-
tion in a given sample solution using °ame photometer. (6)
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