Download AKTU B-Tech 2nd Sem 2016-17 NAS202 Engineering Chemistry Question Paper

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B.TECH.

THEORY EXAMINATION (SEM–II) 2016-17

ENGINEERING CHEMISTRY

Max. Marks : 100

Note: Be precise in your answer. In case of numerical problem assume data wherever not provided.

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SECTION – A

1. Explain the following: 10 x 2 = 20
   1. Define polymer and polymerization.
   2. What do you understand by temporary and permanent hardness of water.
   3. Why ß carotene absorbs light in visible region?
   4. Explain why the value of NCV is greater than GCV.

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   5. Explain the bonding and antibonding molecular orbitals .
   6. What is unit cell? What are its types?
   7. What is meant by elastomers?
   8. Calculate the bond order of O₂?
   9. Predict the number of signals in CH₃CH₂OH.

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   10. Explain Priming and Foaming.

SECTION – B

Attempt any five of the following questions: 5 x 10 = 50

2. 1. What is metallic bond? Explain it on the basis of Molecular Orbital theory.

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   2. With the help of MO diagram, calculate the bond order, nature of the following:
      1. N₂ & O₂
3. 1. Differentiate between addition and condensation polymerization with suitable examples?
   2. Write the method of preparation for the following polymers:
      1. PMMA

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      2. Orlon
      3. Polystyrene
4. 1. Discuss the Zeolite method for water softening.

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   2. The hardness of 1000 liters of a water sample was completely removed by passing it through a zeolite softener. The softener then required 30 liters of NaCl solution containing 1.5 g/l of NaCl for regeneration. Calculate the hardness of the sample of water.
5. 1. Write possible optical isomers in tartaric acid.
   2. What is the difference between enantiomers and diastereoisomers?

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6. 1. Define the terms chromophore and auxochrome in UV spectroscopy.
   2. A compound having concentration 10^-3g/l resulted absorbance value 0.20 at ?max 510 nm using 1.0 cell. Calculate it absorptivity and molar absorptivity values. Molecular weight of compound is 400.
7. 1. What is electrochemical corrosion? Write down the mechanism involved in electrochemical corrosion. Calculate the amount of rust (Fe₂O₃.3H₂O) formed by complete rusting of 1 kg of iron.

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8. 1. Describe the structure of graphite. How it acts as conductor of electricity. Show, how does the S_N² reaction give rise to inverted product while S_N¹ reaction gives a racemic mixture.
9. 1. Show, how does the S_N² reaction give rise to inverted product while S_N¹ reaction gives a racemic mixture

Attempt any two of the following questions: 2 x 15 = 30

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3. 1. What is biogas? How biogas is produced? With the help of diagram, explain Biogas Plant.
   2. What is potable water? What are its chemical requirements?
4. 1. What are bio degradable polymers? Discuss their applications?
   2. How do you prepare the following polymers? (a) Bakelite (b) Perspex (c) Cis-1,4-polyisoprene cross linked through non metal

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5. 1. For a XY₂ bent molecule show various types of stretching and bending vibrations in IR
   2. Calculate temporary and total hardness of a water sample containing: Ca (HCO₃)₂=17.4 mg /lit, Mg (HCO₃)₂ =9.3mg/lit, CaSO₄ = 12.6 mg/lit and MgCl₂ = 8.7 mg/lit.

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