FEDERAL PUBLIC SERVICE COMMISSION

COMPETITIVE EXAMINATION-2018 FOR RECRUITMENT TO POSTS IN BS-17
UNDER THE FEDERAL GOVERNMENT

CHEMISTRY, Paper-1

TIME ALLOWED: THREE HOURS
PART-I(MCQS): MAXIMUM 30 MINUTES
PART-I (MCQS) MAXIMUM MARKS = 20
PART-II MAXIMUM MARKS = 80

NOTE:

• (i) Part-II is to be attempted on the separate Answer Book.
• (ii) Attempt ONLY FOUR questions from PART-II. ALL questions carry EQUAL marks.
• (iii) All the parts (if any) of each Question must be attempted at one place instead of at different places.
• (iv) Candidate must write Q. No. in the Answer Book in accordance with Q. No. in the Q.Paper.
• (v) No Page/Space be left blank between the answers. All the blank pages of Answer Book must be crossed.
• (vi) Extra attempt of any question or any part of the attempted question will not be considered.

PART-II

Q. No.2.

• (a). Explain de Broglie’s hypothesis and derive its equation. How Davisson and Germer proved the dual nature of electron?
• (b). Explain transport number. How it can be determined by Hittorf ’s method for Ag’ ions in AgNO3 solution?

Q. No.3.

• (a). Explain the working of quinhydrone electrode. (5)
• (b). Calculate the standard heat of formation of propane (C3Hs) if its heat of
  combustion is -2220.2 kJ mol’. The heats of formation of CO2(g) and H.0()
  are —393.5 and —285.8 kJ mol’ respectively. (5)
• (c). Describe the criteria of spontaneity of a chemical process. Explain in terms of change in entropy, enthalpy and free energy with derivation of necessary
  equations.(10)

Q.No.4.

• (a). Discussthe factors which can affect the rate of a chemical reaction. (5)
• (b). Explain Arrhenius equation. Discuss Arrhenius concept of activation energy and = explain it by graphical representation.(8)
• (c). Explain enzyme catalysis with examples. Also give some characteristics of this catalysis. (7)

Q. No.5.

• (a). What are colloids? How are they classified? Describe how colloidal solution of
  sulphur can be prepared? (8)
• (b). What is meant by confidence limits? Seven replicate analysis for mercury in natural gas condensate gave 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. (7)
• (c). Explain R¢ 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 Re value? (5)

Q. No. 6.

• (a). What is electrophoresis? Explain its working principle and describe its different (% applications as a separation and characterization technique.
• (b). Explain the paramagnetic behavior of O2 molecule on the basis of molecular (6)
• (c). orbital theory. Explain why the existence of Hez molecule is not possible on the basis of MOT? Explain the molecular shape of [Ni(CN)4]- with the help of valence bond theory. (7)
  Also discuss its magnetic behaviour.

Q. No.7.

• (a). Using VSEPR theory, identify the type of hybridization and draw the structure of  OF 2. What are oxidation states of O and F? (5)
• (b). A buffer of pH 9.26 is made by dissolving x moles of ammonium sulphate and =  0.1 mole of ammonia into 100 mL solution. If pk, of ammonia is 4.74, calculate the value of x. (5)
• (c). Explain 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 it differs from valence bond theory? Also
  explain crystal field splitting. How crystal field stabilization energy of a complex is calculated? (10)
• (b). Write systemic names of following compounds. Ka[NiFos], K3[Fe(CN)6], [Co(NH3)4Cl2]CI, K2[PtCl«], K2[Cu(CN)4]
• (c). Write the coordination number and oxidation state of the metal ion in each of the (5)

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