LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

           B.Sc. DEGREE EXAMINATION – CHEMISTRY

GH 18

FIFTH SEMESTER – APRIL 2008

CH 5500 – PHYSICAL CHEMISTRY – II

 

 

 

Date : 28-04-08                  Dept. No.                                        Max. : 100 Marks

Time : 1:00 – 4:00

 

part – a

            Answer all questions.                                                            (10 ´ 2 = 20 marks)

 

1. Why can’t you use NaCl in salt bridge preparation of a galvanic cell?
2. For the cell reaction at 25° C, Zn½Zn²⁺⁺½½Cu²⁺½Cu     E°_cell = 1.10 V

Calculate equilibrium constant for the  reaction.

3. Define molar conductance of a solution.
4. What is transport number?
5. Calculate the ionic strength of 0.01 M KNO₃
6. 30% of a zero order is complete in 100 min. How long will it take for 60% completion of the reaction?
7. Mention the steps involved in a chain reaction
8. Differentiate adsorption from absorbtion
9. Mention the significance of the equation q =
10. State Grotthus – Drapper’s law.

 

PART – B

            Answer any EIGHT questions.                                            (8 x 5 = 40 marks)

 

11. Derive Nernst equation for a cell reaction.
12. Calculate E°_cell, E_cell, DG°_cell and DG_cell for

Cu½Cu²⁺(0.01 M)½½Ag⁺(0.001 M)½Ag at 298 K.  E°_red  Cu²⁺½Cu and Ag⁺½Ag are 0.34 V

and 0.8 V respectively.

13. Explain the construction and working of calomel electrode.
14. State and explain Kohlrausch’s law of independent migration of ions.
15. Write the electrode reactions and the net reaction of lead storage cell when it serves as source of current.
16. Explain the principle of conductometric acid-base titrations with an example.
17. Explain the mechanism of bimolecular surface reaction.
18. How does Λ vary with concentration for

(i) strong electrolyte        (ii) weak electrolyte

19. The rate of a reaction is doubled on increasing the temperature from 25° C to 35°  Calculate the activation energy of the reaction.  (R = 8.314 JK^-1mol^-1).
20. Derive an expression connecting rate constant and concentration of a II order5 reaction of the type 2A ®
21. Differentiate (i) order from molecularity (ii) EMF and potential difference.           (3 + 2)
22. Define quantum yield of a photochemical reaction. How is it determined?                        (2 + 3)

 

 

 

PART-C

   Answer any FOUR questions.                                                            (4 ´ 10 = 40 marks)

 

23.(a) Explain any two methods of determining order of a reaction.       (6)

(b) t_1/2 of C-14 is 5770 years.  Calculate the rate constant.  Starting from 100 mg
of  C-14 how much of it will remain at the end of 17,310 years.              (4)

24. Discuss the kinetics of unimolecular reaction with relevant derivation of the rate law.
25. Explain any two of the following: (5 + 5)

(a) Quinhydrone electrode and its use.

(b) Evaluation of thermodynamic quantities from EMF data.

(c) H₂-O₂ fuel cell.

(d) Determination of K_sp using conductometry.

26. (a) Explain how transport number of an ion be determined using moving
    boundary method?

(b) Explain the functioning of glass electrode.

27. Explain any two of the following:

(a) Electrochemical series

(b) Cells with transference

(c) Determination of EMF

(d) Weston Cadmium cell

28.(a) Explain the postulates of Langumir adsorption isotherm and hence derive the
equation.

(b) Write briefly on photosensitisation.

 

 

 

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LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

B.Sc. DEGREE EXAMINATION – CHEMISTRY

GH 10

THIRD SEMESTER – APRIL 2008

CH 3500 – PHYSICAL CHEMISTRY – I

 

 

 

Date : 26/04/2008                Dept. No.                                        Max. : 100 Marks

Time : 1:00 – 4:00

part – a

            answer ALL the questions.                                                 (10 ´ 2 = 20 marks)

 

1. Write van der Waal’s equation for ‘n’ moles of the gas and mention the terms involved.
2. Calculate DS for the vapourisation of 1 mole of H₂O(l) at 373 K.

DH_vap = 9720 cal/mol.

3. State Hess’s law of constant heat summation.
4. What is the effect of pressure on the system PCl_5(g) ⇌ PCl_3g) + Cl_2g) at equilibrium?
5. What is chemical potential? Is it extensive or intensive?
6. State reduced phase rule equation.
7. State Henry’s law.
8. What are colligative properties? Give two examples.
9. Define partition coefficient.
10. What is meant by thermodynamic equilibrium constant?

 

PART – B                             (8 ´ 5 = 40 marks)

              Answer any EIGHT questions.

 

11. State any five postulates of kinetic theory of gases.
12. Derive Gibb’s-Helmohltz equation.
13. Draw the phase diagram for water system and apply the phase rule equation to any one point, one line and one area.
14. 1 mole of an ideal, monoatomic gas expands isothermally and reversibly at 27°C from 10 to 100 lit. Calculate q, w, DE, DH and D
15. Differentiate bond energy from bond dissociation energy with a specific example.
16. State Raoult’s law and explain positive deviation from it.
17. How is osmotic pressure of a solution determined experimentally?
18. Derive the relation DG = DG° + RT ln Q and hence deduce an expression for thermodynamic equilibrium constant.
19. State III law of thermodynamics and explain.
20. Explain the phase diagram of phenol-water system.
21. Calculate the freezing point of 0.01 m aqueous solution of K₄[Fe(CN)₆] assuming 80% ionization. k_f for H₂O is 1.86 K kg mol^-1.
22. Derive Nernst distribution law.

 

 

PART – C

            Answer any FOUR questions.                                 (4 ´ 10 = 40 marks)

 

23. Derive Maxwell equations from first principle.
24. Deduce van der Waal’s equation.

 

25. Derive any two of the following. (5 + 5)

(a) PV^g = constant                              (b) Kirchoff’s equation

(c) relation between K_p and K_c             (d)

26. Draw the phase diagram of a simple eutectic system and discuss its salient features.
27. Derive thermodynamically the relation connecting elevation of boiling point of a solution and molality.
28. Explain any two of the following: (5 + 5)

(a) Gibb’s phase rule equation            (b) Azeotropes

(c) Joule-Thomson coefficient           (d) van’t Hoff factor.

 

 

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LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

B.Sc. DEGREE EXAMINATION – CHEMISTRY

DB 17

FIFTH SEMESTER – November 2008

CH 5500 – PHYSICAL CHEMISTRY – II

 

 

 

Date : 03-11-08                     Dept. No.                                        Max. : 100 Marks

Time : 9:00 – 12:00

 

PART – A

 

Answer ALL questions.                                  (10 x 2 = 20 marks)

 

1. What is a reference electrode? Give an example.

 

2. Define EMF.

 

3. What is meant by Hydrogen over voltage?

 

4. Calculate the ionic strength of 0.1M KCl.

 

5. Define order of a reaction.

 

6. What is a Psuedo-unimolecular reaction? Give an example.

 

7. Mention any two factors affecting the enzyme catalysis?

 

8. What is adsorption? Give an example.

 

9. Define quantum yield.

 

10. What is chemiluminesence?

 

PART – B

 

Answer any EIGHT questions.                                   (8 x 5 = 40 marks)

 

11. Explain the experimental method of determining the standard reduction potential

of Zn electrode.

 

12. Explain the working of Weston cell.

 

13. Calculate the EMF of the following electrochemical cell at 25^oC.

 

Cu, Cu²⁺ (a = 0.1 M)  ||  H⁺ (a = 0.01M),  H₂(0.95 atm); Pt E^o_xd cu²⁺| cu 0.34 volt

 

14. Discuss briefly the principle of polarography.

 

15. Explain the term decomposition potential. Discuss its application.

 

16. How is order of a reaction determined experimentally using half life method?

 

17. Explain the kinetics of unimolecular reaction using Luidemann theory.

 

18. Calculate the activation energy of a reaction whose rate constant is tripled by a 10^oC rise in temperature in the vicinity of 27^oC.

 

19. Derive Langmuir adsorption isotherm.

 

20. Discuss the general characteristics of catalytic reaction.

 

21. Derive an expression for rate constant of a second order reaction with equal concentration of

reactants.

 

22. Explain the basic concepts of photosensitized reactions.

 

PART – C

 

Answer ANY FOUR questions.                                 (4 x 10 = 40 marks)

 

23. a) Derive the Nernst equation for a cell reaction.                       (5)

 

1. Derive the emf of a concentration cell with transference. (5)

 

24. a) Explain the determination of pH using quinhydrone electrode.  (5)

 

1. b) How will you prove electrochemically that mercurous ion exists as Hg₂²⁺   (5)

 

25. Explain Debye Huckel Theory of strong electrolytes.

 

26. Explain the collision theory of bimolecular reactions. What are its limitations.

 

27. a) Explain the influence of ionic strength on the rates of ionic reactions.  (5)

 

1. b) Discuss on Absolute reaction rate theory.                                               (5)

 

28. Derive Michaelis – Menton equation for a single substrate enzymatic reaction and explain.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

   B.Sc. DEGREE EXAMINATION – CHEMISTRY

DB 06

THIRD SEMESTER – November 2008

CH 3500 – PHYSICAL CHEMISTRY – I

 

 

 

Date : 06-11-08                     Dept. No.                                        Max. : 100 Marks

Time : 1:00 – 4:00

PART – A

Answer ALL questions.                                  (10 x 2 = 20 marks)

 

1. State the first law of thermodynamics.

 

2. Write Van der Waals equation for ‘n’ moles if a gas.

 

3. Distinguish between state function and path function.

 

4. Explain the term Eutectic point with an example.

 

5. Define the congruent melting point.

 

6. Explain the term degrees of freedom.

 

7. What are azeotropes? Give an example.

 

8. State Raoult’s law.

 

9. Find the molal elevation constant of water which evaporates at 100^oC with the absorption of 40669.2 J per mole (R = 8.134 J K^-1 mol^-1).

 

10. 0.1 M aq. solution of KNO₃ shows an osmotic pressure of 4.5 atm at 300K, while the calculated one is 2.5 atm. What is the Van’t Hoff factor ‘i’ for the solution.

 

PART – B

Answer any EIGHT questions.                                   (8 x 5 = 40 marks)

 

11. State the postulate of the Kinetic theory of gases.

 

12. Define C_p and C_v. Derive the relationship between them for an ideal gas.

 

13. Prove that TV^γ-1 = constant for an adiabatic expansion of an ideal gas.

 

14. Calculate the entropy of mixing of one mole of oxygen gas and two moles of hydrogen gas, assuming that no chemical reaction occurs and the gas mixture behaves ideally.

 

15. Derive Clausius-Calpeyron ^equation.

 

16. Draw and explain the phase diagram of water system.

 

17. Give the general account of three components system.

 

18. Derive thermodynamically the Gibb’s phase rule.

 

19. Discuss the principle and application of Fractional distillation.

 

20. Explain the effect of adding NaCl to the CST of phenol water system.

 

21. Discuss the Van’t Hoff’s theory of dilute solutions.

 

22. The molar heat of vaporisation of water at 100⁰ C is 40.585 kJ mol^-1. At what temperature will a solution containing 5.60 g of glucose per 1000 g of water boil?

 

PART – C

Answer ANY FOUR questions.                                 (4 x 10 = 40 marks)

 

23. a) Derive Kirchoff’s equation.                            (5)

 

1. b) Explain Joule-Thomson effect.                       (5)

 

24. a) State and explain the third law of thermodynamics.  (5)

 

1. b) Derive Gibb’s Helmholtz equation.                            (5)

 

25. a) Explain the phase diagram of Pb-Ag system.             (4)

 

41. b) The vapour pressure of water at 100^oC is 760 mm. What will be the vapour pressure at 95^oC?  The heat of vaporisation of water in this temperature range is 41.27 kJ per mole.

(6)

26. Discuss the phase diagram of formation of compound with congruent melting point.

 

27. a) State and explain the Henry’s law.   How is it related to Raoult’s law?                    (5)

 

1. Write notes on steam distillation. (5)

 

28. a) Derive thermodynamically nernst distribution law.                                                    (6)
29. b) Explain one of its applications.                                                                                   (4)