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. No. 2. (a) Explain de Broglie’s hypothesis and derive its equation. How did Davisson and Germer prove the dual nature of electrons? (10) (b) Explain transport number. How can it be determined by Hittorf’s method for Ag⁺ ions in AgNO₃ solution? (10)
Q. No. 3. (a) Explain the working of the quinhydrone electrode. (05) (b) Calculate the standard heat of formation of propane (C₃H₈) if its heat of combustion is –2220.2 kJ mol⁻¹. The heats of formation of CO₂(g) and H₂O(l) are –393.5 and –285.8 kJ mol⁻¹ respectively. (05) (c) Describe the criteria of spontaneity of a chemical process. Explain in terms of change in entropy, enthalpy, and free energy with the derivation of necessary equations. (10)
Q. No. 4. (a) Discuss the factors which can affect the rate of a chemical reaction. (05) (b) Explain the Arrhenius equation. Discuss the Arrhenius concept of activation energy and explain it by graphical representation. (08) (c) Explain enzyme catalysis with examples. Also give some characteristics of this catalysis. (07)
Q. No. 5. (a) What are colloids? How are they classified? Describe how a colloidal solution of sulphur can be prepared. (08) (b) What is meant by confidence limits? Seven replicate analyses for mercury in natural gas condensate gave the following results in ng/mL: 21.9, 21.5, 19.9, 21.3, 21.7, 23.8, 24.7. Calculate the 95% and 99% confidence limits for these measurements. (07) (c) Explain R_f value. Suppose that components of a mixture are separated by paper chromatography using a non-polar solvent like hexane. Describe and explain how the polarity of a compound in the mixture will affect its R_f value. (05)
Q. No. 6. (a) What is electrophoresis? Explain its working principle and describe its different applications as a separation and characterization technique. (10) (b) Explain the paramagnetic behavior of the O₂ molecule on the basis of molecular orbital theory. Explain why the existence of the He₂ molecule is not possible on the basis of MOT. (06) (c) Explain the molecular shape of [Ni(CN)₄]²⁻ with the help of valence bond theory. Also discuss its magnetic behaviour. (04)
Q. No. 7. (a) Using VSEPR theory, identify the type of hybridization and draw the structure of OF₂. What are the oxidation states of O and F? (05) (b) A buffer of pH 9.26 is made by dissolving x moles of ammonium sulphate and 0.1 mole of ammonia into a 100 mL solution. If pK_b of ammonia is 4.74, calculate the value of x. (05) (c) Explain the soft and hard acids and bases (SHAB) concept with examples. How is it able to explain the stability of complexes and reaction rates? (10)
Q. No. 8. (a) Explain crystal field theory. How does it differ from valence bond theory? Also explain crystal field splitting. How is the crystal field stabilization energy of a complex calculated? (10) (b) Write the systematic names of the following compounds: K₄[NiF₆], K₃[Fe(CN)₆], [Co(NH₃)₄Cl₂]Cl, K₂[PtCl₆], K₂[Cu(CN)₄]. (05) (c) Write the coordination number and oxidation state of the metal ion in each of the above stated complexes. (05)
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) Define Resonance and Resonance effect. (10) (b) Write short notes on the following: (5 + 5 = 10) (i) Tautomerism (ii) Hyperconjugation
Q. No. 3. (a) Complete the following reactions: (2 x 8 = 16) (i) CH₃–CH=CH₂ + KMnO₄ + H₂O (ii) CH₃–CH=CH₂ + H₂ / Ni (under pressure) (iii) CH₃–CH=CH₂ + dil. H₂SO₄ (iv) CH₃–CH=CH₂ + CH₃–CHO (Ozonolysis/Addition pathways) (v) CH₃–CH=CH₂ + Br₂ / CCl₄ (vi) CH₃–C≡C–CH₃ + Na / liq. NH₃ (vii) CH≡CH + NaNH₂ (viii) CH≡CH + H₂O (in the presence of H₂SO₄ / HgSO₄) (b) 1-Butyne forms a precipitate with an ammoniacal solution of silver nitrate whereas 2-Butyne does not. Why? (04)
Q. No. 4. Explain the electrophilic substitution reaction mechanism with the help of: (10 + 10 = 20) (i) Nitration (ii) Sulphonation
Q. No. 5. (a) Distinguish between the following: (4 x 3 = 12) (i) Configuration and conformation (ii) Enantiomers and Diastereomers (iii) R configuration and S configuration (b) Define specific rotation. How do you measure it using a polarimeter? (08)
Q. No. 6. (a) What do you mean by the setting of cement? (10) (b) Discuss the future of the cement industry in Pakistan. (10)
Q. No. 7. (a) Explain the Aldol condensation reaction with examples. (10) (b) What are proteins? (05) (c) Explain the biosynthesis of cholesterol. (05)
Q. No. 8. Explain the following concepts: (4 x 5 = 20) (a) Beer-Lambert Law (b) Woodward-Fieser Rules (c) Hooke’s Law (d) Basic principles of NMR spectroscopy (e) Chemical Shift
