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JAMB Chemistry 2013 Question 25

Question 25

Electrolysis

Calculate the volume in cm3 of oxygen evolved as s.t.p. when a current of 5 A is passed through acidified water for 193 s [F = 96500 Cmol−1, Molar volume of a gas at s.t.p. = 22.4 dm3]

  1. A.224.000
  2. B.0.056
  3. C.0.224
  4. D.56.000
Show the answer and explanation

Answer: D (56.000)

Explanation

Q = 5 × 193 = 965 C = 0.01 F. Each mole of O2 needs 4 F, so 0.0025 mol × 22 400 cm3 = 56 cm3.