BALOCHISTAN PUBLIC SERVICE COMMISSION
COMPETITIVE EXAMINATION FOR THE POSTS OF SECTION OFFICERS (B-17)
CHEMISTRY
MARKS: 150
JUNE 09, 2003
TIME: 03 HOURS
NOTE: DO ANY FIVE QUESTIONS SELECTING AT LEAST ONE AND NOT MORE THAN TWO FROM EACH SECTION. ALL QUESTIONS CARRY EQUAL MARKS.
SECTION – I (PHYSICAL)
Q-1. (a) Derive gas laws from kinetic theory of gases.
(b) Some atoms in the molecules have number of electrons in the valence shell short of the octet or in excess of the octet. Illustrate with examples two each.
(c) Define the following in short and give examples.
(i) Polar and non-polar bonds.
(ii) Single and multiple bonds.
(iii) Covalent and ionic bonds.
(iv) Sigma and pi bonds.
(v) Hydrogen bonding.
(vi) Dative bond.
Q-2. (a) Differentiate clearly with the help of examples between nuclear reactions and chemical reactions.
(b) State and explain azimuthal and magnetic quantum numbers. Give the shapes and orientation of the orbitals.
(c) How gases can be liquefied? Give only one method.
Q-3. (a) Explain Hess’s law of constant heat summation.
(b) How many ways are there for expressing the concentration of a solution. Explain.
(c) Calculate the molarity of the solution prepared by dissolving 69.3 grams of pure KOH in 750 ml of water.
Q-4. (a) What is mass defect and nuclear binding energy? Does nuclear binding energy relate to the stability of the nucleus? Explain.
(b) Define refractive index. How it is measured by Abbe’s refractometer?
(c) Define heat of fusion, heat of vaporization and heat of transition.
SECTION – II (INORGANIC)
Q-5. (a) What do you understand by the term mono-basic, di-basic and tri-basic? Explain.
(b) Explain common ion effect. Elaborate its importance and applications.
(c) Nitrogen has five electrons in its valence shell. It forms NCl3 instead of NCl5. Give reason.
Q-6. (a) Discuss in detail the extraction of copper from its ore, giving reactions in all operative steps.
(b) How many nitrogen fertilizers do you know? Explain only one method for the preparation of ammonium nitrate on commercial scale.
(c) Illustrate differences between carbon and silicon with reference to catenation.
Q-7. (a) Explain electrochemical series. Exhibit its applications.
(b) Account for the following:
(i) AlCl3 is good reducing agent/catalyst.
(ii) H2S is gas while H2O is liquid.
(iii) First IP value is always less that 2nd IP value of an atom.
(iv) Which group in the periodic table possesses the highest IP value and why?
(v) Angular structure of water instead of linear.
SECTION – III (ORGANIC)
Q-8. (a) How is benzene diazonium chloride synthesized? Show its reactions in which nitrogen atom of diazonium group is retained.
(b) Synthesize benzene, iodobenzene and phenol from benzene diazonium chloride.
Q-9. (a) Elaborate the reactions of alcohols in which O-H and C-O bonds are cleaved.
(b) Give the acidic reactions of phenols.
(c) What are amides? How are they prepared?
Q-10. (a) Complete the following reactions:
(i) CH3-CH=CH2 + HBr –peroxide–>
(ii) CH3-CH2-OH –conc. H2SO4 / heat–>
(iii) C2H6 + 3O2 –Ni–>
(iv) CH3COONa + NaOH –CaO / heat–>
(v) C2H5MgI + CH3COCl –ether–>
(b) Write notes on Cannizaro reaction and Aldol Condensation with mechanisms.
The End
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