Federal Public Service Commission (FPSC)
Competitive Examination for Recruitment to BPS-17 Posts under the Federal Government
Time Allowed: 3 Hours
MAXIMUM MARKS: 100 Marks
CHEMISTRY, PAPER-I
PART-II
Attempt FIVE questions in all, Including Questions No.1 which is COMPULSORY, All questions carry EQUAL marks.
Q. 2. (a) Describe the assumptions of Bohr’s atomic model. Based on Bohr’s calculations, establish the energy expression of the rotation of electrons in Hydrogen-like atomic species. (08)
(b) Derive de-Broglie’s equation for the dual nature of matter. Apply this equation to microscopic and macroscopic properties of substances. (06)
(c) What are the postulates of Quantum Mechanics? (06)
Q. 3. (a) What is the Third law of thermodynamics? How is it used to determine the absolute entropies of substances? (07)
(b) Discuss the isothermal expansion of a gas and derive the equation for the work done due to the expansion of an ideal gas. (07)
(c) Explain the law of corresponding states. (06)
Q. 4. (a) Deduce the rate expression for a 2nd order reaction where both the initial concentration terms are the same. What is the half-life period for this 2nd order reaction? (10)
(b) What is activation energy? How can it be determined experimentally? (05)
(c) Write a note on the Transition State Theory of reaction rates. (05)
Q. 5. (a) Develop a relation among phase, component, and degree of freedom (Phase Rule). Draw a complete phase diagram for the water system. (10)
(b) What is catalysis? Differentiate between positive and negative catalysis. (06)
(c) What is stoichiometry? Explain it with the help of examples. (04)
Q. 6. (a) State and explain the Lowry-Bronsted theory and Lewis theory of acids and bases. In what way does the Lewis theory differ from the Bronsted theory? (08)
(b) Explain with the help of examples why the pH of a buffer solution does not change significantly upon the small addition of acids and bases. (06)
(c) What are indicators? How can a suitable indicator be chosen for a titration? Discuss. (06)
Q. 7. (a) Give an account of the phenomena of isomerism in coordination compounds with suitable examples. (08)
(b) Describe the extraction of thorium from monazite sand. (06)
(c) Compare the properties of lanthanides and actinides. (06)
Q. 8. (a) Explain Kohlrausch’s Law. Give its major applications. (07)
(b) What is meant by the transport number of ions? Give different experimental methods for the determination of transport numbers. (07)
(c) What is specific conductance? How can it be determined by using a Wheatstone bridge? (06)
CHEMISTRY, PAPER-II
Attempt FIVE questions in all, Including Questions No.1 which is COMPULSORY, All questions carry EQUAL marks.
PART-II
Q. No. 2. (a) Elaborate on optical isomerism with appropriate examples. (10)
(b) Express the concept of resolution of racemic mixtures and its applications. (05)
(c) Explain geometric isomerism in cyclic compounds. (05)
Q. No. 3. (a) Prepare a plausible synthesis for each of the following transformations: (2 x 6 = 12)
[Transformation A: Alkene functionalization to simple alkyl halides/alkanols]
[Transformation B: Synthesis of a cyclic ketone / Cyclohexanone derivative]
[Transformation C: Preparation of an allylic or secondary alcohol]
[Transformation D: Synthesis of a diol or glycol derivative]
[Transformation E: Formation of a vicinal or geminal dibromide]
[Transformation F: Alkene addition yielding a 1,2-dibromo configuration]
(b) Explain the type of hybridization in 1,3-Butadiene. (04)
(c) Mention any three general methods for the preparation of Alkynes. (04)
Q. No. 4. (a) Describe the necessary conditions and reagents required to convert benzene into the following: (8)
Nitrobenzene, Ethylbenzene, Cyclohexane, Benzaldehyde, Benzoic acid, and Chlorobenzene.
(b) Draw all possible structures of aromatic compounds with the molecular formula C₉H₁₂ containing a benzene ring. (06)
(c) How do you account for the fact that phenol is more easily attacked by electrophiles than nitrobenzene? (06)
Q. No. 5. (a) Outline the stepwise reaction mechanism for the following reactions: (06)
(i) S_N1 reaction mechanism (e.g., hydrolysis configurations of alkyl halides).
(ii) S_N2 reaction mechanism (e.g., nucleophilic substitution via cyanide/hydroxide attacks).
(b) Discuss the various factors affecting an S_N2 reaction: nature of substrate, solvent, catalyst, and the leaving group. (08)
(c) How does methyl iodide react with the following reagents? (06)
Acetic acid, Mg metal, Alcoholic KOH, and Na metal.
Q. No. 6. (a) Describe two methods for the preparation of salicylic acid. How would you convert it into: (i) Phenol, (ii) Salol, (iii) Benzoic acid, and (iv) Aspirin? Give at least two medicinal uses of salicylic acid. (10)
(b) How will you obtain the following from a suitable monocarboxylic acid? (06)
(i) Isobutane, (ii) Butanone, (iii) Benzamide, (iv) Propionaldehyde.
(c) Describe the complete mechanism of acid-catalyzed esterification of a carboxylic acid. (04)
Q. No. 7. (a) An unknown substance shows a molecular ion peak at m/z = 170 with a relative intensity of 100%. The M+1 peak has a relative intensity of 13.2% and the M+2 peak has an intensity of 1.00%. What is the molecular formula for this substance? (10)
(b) Mention the various tools and fragmentation rules used to interpret mass spectra. (05)
(c) What is the nitrogen rule in mass spectrometry? Explain it with suitable examples. (05)
Q. No. 8. (a) Elucidate the various biochemical steps involved in Glycolysis (Embden-Meyerhof-Parnas pathway). (10)
(b) Express the role and net balance of ATP in Glycolysis. (05)
(c) Describe the anaerobic pathway that leads to the formation of Lactic acid. (05)
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