A 500 ml of 0.2 M Cd²⁺ is electrolyzed with a current of 96.5 If the remaining concentration of Cd²⁺ ions is 0.1 M, then the duration of electrolysis is:
Correct answer: D. 100 s
- A. 50 s
- B. 75 s
- C. 125 s
- D. 100 s
Explanation
The change in moles of Cd²⁺ is (0.2 - 0.1.M) × 0.5L = 0.05 mol. The reaction Cd²⁺ + 2e⁻ → Cd requires 2 moles of electronsper mole of Cd, so 0.1 moles of electrons are needed. Total charge Q = 0.1 mol × 96500 C/mol = 9650 C. Time t = Q/I = 9650 C / 96.5 A = 100 s.
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