A copper plating cell is connected in series with a silver coulometer. During a run, $3.24 g$ of silver is deposited in the coulometer and $0.762 g$ of copper is deposited in the plating cell. The current efficiency of copper deposition is (Ag = 108, Cu = 63.5)

Answer: B

Silver deposited

= 3.24/108 = 0.0300 mol

, so

0.0300 mol

of electrons passed through both cells. Theoretical copper

= 0.0150 \times 63.5 = 0.9525 g

. Efficiency

= \frac{0.762}{0.9525} \times 100 = 80.0%