CHEMISTRY

CHEMISTRY
SEM.II, 2011
B.TECH
UTTARAKHAND TECHNICAL UNIVERSITY 

Time: 3 Hours

Total Marks :100

SECTION A

Attempt any 4 question

1. On the basis of molecular orbital theory explain the paramagnetic nature of O₂ molecule.
2. Explain conductivity in conductors, semiconductors and insulators with the help of band theory.
3. What is a hydrogen bond? Explain why p-nitrophenol is more soluble in water than o-nitrophenol.
4. What is Bragg's Law? How the density of a unit cell can be calculated?
5. Give the mechanism of the following reactions:
   (i) Beckmann Rearrangement
   (ii) Pinacol-pinacolonone rearrangement.
6. What is E-Z system of nomenclature? In what way it is better than cis-trans nomenclature?

SECTION B

Attempt any 4 question

1. Derive the equation for the rate constant of a second order reaction where concentrations of both the reactants are different. Under which condition a second order reactions behaves like a first order reaction?
2. What is activation energy? How is the rate constant of reaction related to the activation energy for a reaction can be determined?
3. What is a buffer solution? How it is prepared? Explain the buffer action.
4. What is electrochemical theory of corrosion? Discuss the mechanism of electrochemical corrosion of iron.
5. Write a short note on the zeolite process for watersoftening. What are the advantages of zeolite process over LS process?
6. State Kohlrausch’s law and give account of the various application of this law.

SECTION C

Attempt any 2 question

1. (i) Explain the process of vulcanization. Give the preparation (equation only) and uses of two synthetic rubbers
   (ii) Write short note on:
   (a) Bulk polymerization
   (b) Emulsion polymerization
2. (i) Give the preparation and uses of PMMA and polyurethane.
   (ii) What are conducting polymers? How polymers can be converted to their conducting form? Give two examples of such polymers.
3. Discuss in detail different types of polymerization methods.

SECTION D

Attempt any 2 question

1. (i) What are the properties of a good fuel? Define the gross and net calorific values for a fuel.
   (ii) A bomb calorimeter experiment using 0.8 g of coal gave an increase in temp of 2.2⁰C. The weight of waterin the calorimeter was 1250 g and the water equivalent of calorimeter was 125 g. Calculate the gross calorific value of the coal sample. If the coal contained 5.2% ofhydrogen calculate the net calorific value.
2. Write short note on any four of the following:
   (i) Bio-mass
   (ii) Bio-diesel
   (iii) Pour point
   (iv) Cloud point
   (v) Viscosity Index.
3. (i) Distinguish between thin-film and boundary lubrication.
   (ii) How are liquid lubricants classified? Discuss one important method for refining of mineral oils.

 SECTION E

Attempt any 2 question

1. (i) An organic compound with molecular formula C₃H₃Cl₅gave the following proton NMR data:
   (a) triplet at δ 4.52 (1H)
   (b) doublet at δ 6.07 (2H)
   Identify the compound.
   (ii) What do you understand by shielding and deshielding in NMR? Define chemical shift.
2. (i) Indicate how will you differentiate between the following pairs of compound by NMR spectroscopy:
   (a) Phenol and cyclohexanol
   (b) CH₃-C≡ C-CH₃ and CH₃-CH₂ - C≡ CH
   (c) CH₃-CH₂-OH and CH₃-COOCH₃
   (d) CH₃-CH₂-CH₂-NH₂ and (CH₃)₃N
   (e) CH₃-CH₂-OH and CH₃-O-CH₃
   (ii) For a linear triatomic molecule AB show different modes of vibrations in IR.
3. (i) Explain the working of a mass spectrometer with the help of a neat diagram.
   (ii) A standard hard water sample contains 1.5 g of CaCO₃ equivalent hardness per liter. 20 mL of EDTA solution, while 100 mL of the sample water required 18 mL EDTA. The sample water after boiling required 12 mL EDTA solution. Calculate the temporary and permanent hardness of the sample water in ppm.