PUNJAB PUBLIC SERVICE COMMISSION
COMBINED COMPETITIVE EXAMINATION
FOR RECRUITMENT TO THE POSTS OF
PROVINCIAL MANAGEMENT SERVICE, ETC
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.
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.
