7HD – October 1999

Part A (20 x 2 = 40 Marks)

  1. Define an electrochemical cell
  2. What is e.m.f?
  3. What is reduction potential?
  4. Explain standard electrode potential
  5. What is fuel cell?
  6. What is limiting diffusion current?
  7. Explain electrocatalysis
  8. Define reversible and irreversible cells
  9. What is galvanic series?
  10. Define chemical corrosion
  11. What is passivity?
  12. Explain erosion-corrosion
  13. What is anodic protection?
  14. Classify the protective coatings
  15. What is tinning?
  16. What is varnish?
  17. Site with example anode impurities
  18. Define the term cycle life
  19. What is solid electrolyte?
  20. Give two systems of electro refining

    Part B (5 x 12 = 60 Marks)

  21. (a) (i) Explain the procedure for the determination of electrode conductance

    (ii) Write a note on conductivity cells

    Or

    (b) What is over voltage? Explain the methods to measure over voltage. What are the factors affecting over voltage?

  22. (a) Explain in detail the application of electrochemical analysis
    Or

    (b) Explain the method of determination of electrode potential of zinc electrode

  23. (a) (i) What are the causes of caustic embrittlement?

    (ii) Discuss the problem of stray current corrosion in buried pipelines

    Or

    (b) (i) Enumerate the factors that affect atmospheric corrosion

    (ii) Write a note on marine corrosion

  24. (a) (i) Write down the electrochemical reactions that occur during discharging and charging of lead acid cell (6)

    (ii) Discuss the performance characteristic of a Nickel-Cadmium cell (3)

    (iii) Write a note on Lechlanche dry cell (3)

    Or

    (b) (i) Discuss the actual efficiency of an electrochemical energy converter

    (ii) Explain why an electrochemical cell does not work at the equilibrium potential value

  25. (a) (i) Explain in detail the various theories that describe the metal electrode – solution interface (9)

    (ii) Write notes on function of separators in battery systems. Give examples (3)

    Or

    (b) Explain the reaction mechanism, construction, performance characteristic and applications of Silver-Zinc batteries.