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JAMB Chemistry 1990 Question 22

Question 22

Electrolysis

If 10.8 g of silver is deposited in a silver coulometer connected in series with a copper coulometer, the volume of oxygen liberated is [Ag = 108, Cu = 64, GMV at s.t.p = 22.40 dm3]

  1. A.0.56 dm3
  2. B.5.60 dm3
  3. C.11.20 dm3
  4. D.22.40 dm3
Show the answer and explanation

Answer: A (0.56 dm3)

Explanation

10.8 g of silver is 0.1 mol, so 0.1 faraday passed. Oxygen needs 4 faradays per mole (4OH− → O2 + 2H2O + 4e−), giving 0.025 mol × 22.4 = 0.56 dm3.