PUNJAB PUBLIC SERVICE COMMISSION
COMBINED COMPETITIVE EXAMINATION FOR
RECRUITMENT TO THE POSTS OF
PROVINCIAL MANAGEMENT SERVICE-2019
SUBJECT: CHEMISTRY (PAPER – II)
TIME ALLOWED: THREE HOURS MAXIMUM MARKS: 100
NOTE: Attempt Five Questions in All. Attempt in Urdu or English.
Q No. 1: (i) Draw the structures of the following compounds: (5 Marks)
(a) Spiro [2.4] heptane (b) Bicyclo [2.2.2] cyclo octane (c) Hexanedioic acid (d) 4-oxobutanoic acid (e) Ethanoic anhydride
(ii) Justify the following statement: (2 x 5 = 10 Marks)
(a) Dimethyl amine is stronger base than methyl amine which is stronger than ammonia
(b) Phenol is stronger than ethanol
(c) m-chlorobenzoic acid is a stronger acid than p- chlorobenzoic acid
d) Pyrrole is a weaker base than Pyridine
iii) Draw the resonance structures of the following compounds: (5 Marks)
(a) CH2 = CH-CH3 (b) CH3 = CH-O-CH3 CH3-N=N=N (d) CH2=CH-C=N (e) CH3-C-CH2-C-OC2H5
Q No. 2: (i) Methanol is a good solvent for UV but not for IR Spectroscopy. Explain the fact. (5 Marks)
(ii) Briefly describe the basic difference between Beer’s and Lambert’s laws of absorption of light. (5 Marks)
(iii) Explain the working of double beam IR instrument with special on the formation of a solution and recording of absorbance. (10 Marks)
Q No. 3: (a) Illustrate the difference between the following with examples: (3 + 5 + 4 + 5 = 17)
(i) Conjugation and Hyperconjugation.
(ii) Mesomeric Effect and Inductive Effect.
(iii) Chromophore and Auxochrome.
(iv) Electromeric Effect and Resonance Effect.
(b) Why esters have low boiling points than their corresponding acids? (3 Marks)
Q No. 4: (a) Explain the principle of UV and IR Spectroscopy. (3.5 + 3.5 = 7 Marks)
(b) How would you distinguish between ethane ethylene and acetylene by IR spectroscopy? (6 Marks)
(c) Differentiate between Bathochromic Shift and Hypsochromic Shift. (5 Marks)
(d) What is the formula for absorbance of a substance in Electronic Spectroscopy? (2 Marks)
Q No. 5: (i) Explain the steps involved in the phenomenon of “Walden Inversion”. (5 Marks)
(ii) Discuss the role of Nicol Prism for plane of polarized light. (5 Marks)
(iii) Sketch the energy profile diagram and shapes of boat, twist boat, half chair and chair conformations of cyclohexane. (10 Marks)
Q No. 6: (i) Differentiate between the following terms with the help of appropriate examples.
(a) Fats and oils (b) Soap and detergents (c) Lipids and wax (d) Iso-electronic point and flash- point. (2 x 4 = 8 Marks)
(ii) Proteins exhibit a variety of coloured reactions, describe any four of these. (8 Marks)
(ii) Hydrogen bonding plays an important role in protein structure, prove it. (4 Marks)
Q No. 7: (a) What are Carbohydrates? Discuss their classification. (2 + 6 = 8 Marks)
(b) How do you differentiate between paper partition and adsorption paper chromatography? (6 Marks)
(c) Define Detergent. What are its types and how it is different from soap? (2 + 2 + 2 = 6 Marks)
Q No. 8: (a) Explain the difference between chain growth and step growth polymerization? (6 Marks)
(b) Write a brief note on the following: (3.5 x 4 = 14 Marks)
(i) TLC (ii) Functions of Lipids (iii) PTFE and its applications (iv) P-type and N-type Semiconductors