PMS Chemistry Paper 1


PUNJAB PUBLIC SERVICE COMMISSION
COMBINED COMPETITIVE EXAMINATION
FOR RECRUITMENT TO THE POSTS OF
PROVINCIAL MANAGEMENT SERVICE, ETC
CHEMISTRY (OPTIONAL) PAPER-I
TIME ALLOWED: 3 HOURS                      MAXIMUM MARKS: 100
Note: Attempt any FIVE questions only. Write answers in English.
Q.1:      (a) Using a diagram, explain the variation of molecular energy with internuclear separation.    (10)(b) What is the primary assumption of the VSEPR model?
Explain the difference between square-pyramidal and trigonal bi-pyramidal arrangement in terms of VSEPR. Predict the shape of an SF, molecule. (10)
Q.2:      (a) What are the mineral sources for copper? Describe in detail
the information which can be obtained for 3d metals using a FROST diagram.      (10)
(b) On the basis of trends in the 3d series, suggest possible M2• aqua ions for use as reducing
agents, and write a balanced equation for the reaction of one of these ions 
with 02 in acidic solution.                                         (5)
(ii) Comment on the 2+ oxidation states of 4d and 5d elements.     (5)
Q.3:      (a) Explain with the help of a flow sheet diagram, the electrolytic process of caustic soda manufacturing.       (10)
(b) Give a detailed comparison between dry and wet processing of cement manufacturing.      (10)
Q.4:      (a) Discuss the physical origin of quantization energy for a particle confined to moving inside a one dimensional box or on a ring.                                         (10)
(b) Use EHT to calculate the energies of the three molecular orbitals in an Fir molecule ion treated as an equilateral triangle of side R - 3.25a0 (170 pm).  (10)
Q.5:      (a) Calculate the work done when 50g of iron reacts with HCI to produce hydrogen gas in:      (5,5)
(i) a closed vessel of fixed volume, (ii) an open beaker at 25°C.
(b) The molar constant pressure heat capacity of a certain solid at 10K is 0.43110 mo14. What is its molar entropy at that temperature?                                           (10)
Q.6:      (a) Suggest a calibration procedure for a Na selective electrode, in which the values of E,p,1 and L are measured experimentally. Assume that K. is the only interfering species.  (10)
(b) Distinguish between galvanic and electrolytic cells.         (10)
Q.7:      (a) Define Nuclear Fission and Nuclear Fusion processes. Discuss their comparative features.
(b) Outline a method for preparation of CAN pellets. Distinguish between calcium superphosphate and Triple Superphosphate.

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