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LOYOLA COLLEGE (AUTONOMOUS), CHENNAI 600 034
B.Sc.DEGREE EXAMINATION -CHEMISTRY
FOURTH SEMESTER APRIL 2018
CH 4504 CH 4502 ELECTROCHEMISTRY
Date: 20-04-2018 Dept. No. Max. 100 Marks
Time: 09:00-12:00
PART A
Answer ALL questions: (10x2=20 Marks)
1. What is meant by standard electrode potential?
2. Explain the term electrochemical series.
3. Mention the two uses of Salt bridge
4. What are fuel cells?
5. Calculate the ionic strength of 0.25 M K2SO4 solution.
6. State Kohlraush's law.
7. Define the term activity and activity coefficient.
8. Write Debye Huckel-onsager equation and explain the terms involved in it.
9. Define the term hydrogen over voltage.
10. Write the Ilkovic equation and explain the terms involved.
PART B
Answer any EIGHT questions: (8x5=40 Marks)
11. Explain metal- insoluble salt electrode with a diagram and write down its electrode
reaction.
12. Mention any three significance of electrochemical series.
13. What are the different types of electrodes and write the electrode reaction for any two
types of electrodes?
14. Derive an expression for the EMF of a concentration cell with transference.
15. How would you determine the pH of a given solution using glass electrode.
16. Explain the principle in potentiometric titration of a solution of strong acid against
standard solution of a strong base.
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17. Discuss the Arrhenius theory of electrolytic dissociation and mention any two of its
limitations.
18. A potential of 12 volts was applied to two electrodes placed 20 cm apart, a dilute solution
of ammonium chloride was placed between the electrodes when NH4+ ion was found to
cover a distance of 1.6 cm in one hour. What is the mobility of NH4+ ion.
19. Mention the advantages of conductometric titrations titrations
20. Explain the effect of temperature on conductance
21. Discuss in detail the Debye Huckel theory of activity coefficient.
22. Explain in detail decomposition potential ii) concentration polarization
PART C
Answer any FOUR questions: (4x10=40 Marks)
23. Explain the construction and working of tester saturated standard cell with a neat
diagram
24. a. Explain the measurement of EMF using potentiometer.
b. Derive Nernst equation.
25. The EMF of the cell Cd, CdCI2.5H2O(sat) AgCI(s). Ag with the following cell reaction
2 AgCI(s) CdCI2.5 2 H2O satu 2 Ag is 0.6753 V at 025 C and 0.6915 V at
0 0 C. Calculate the free energy change enthalpy change and entropy change
of the cell reaction at 250 C.
26. Define the transport number of an ion and explain its determination using moving
boundary method.
27. a. What is the principle of conductometric titration? Discuss the titration curves
obtained in weak acid Vs strong base.
b. Explain how separation of metals is carried out by electrolytic separation.
28. Write notes on asymmetric effect ii) electrophoretic effect