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JAMB Chemistry 1982 Question 32

Question 32

Electrolysis

Which of the following statements is correct during the electrolysis of a caustic soda solution using platinum electrodes?

  1. A.Oxygen gas is given off at the cathode
  2. B.Hydrogen gas is given off at the anode
  3. C.Sodium metal is deposited at the anode
  4. D.Sodium metal is deposited at the cathode
  5. E.Alkalinity at the cathode increases.
Show the answer and explanation

Answer: E (Alkalinity at the cathode increases.)

Explanation

At the cathode water is reduced to hydrogen gas and OH− ions, so the solution there becomes more alkaline. Oxygen comes off at the anode and no sodium is deposited.