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JAMB Chemistry 2001 Question 26

Question 26

Electrolysis

What current in amperes will deposit 2.7g of aluminium in 2 hours? [Al = 27, F = 96 500 C mol−1]

  1. A.32
  2. B.8
  3. C.4
  4. D.16
Show the answer and explanation

Answer: C (4)

Explanation

Al3+ + 3e− → Al, so 27 g needs 3 × 96 500 C and 2.7 g needs 28 950 C. I = Q ÷ t = 28 950 ÷ (2 × 3600) ≈ 4 A.