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33. A direct current of 0.1 A is passed for 2 hours through a solution of cuprocyanide (), resultingElectrochemistry Chemistry Question

Question

33. A direct current of 0.1 A is passed for 2 hours through a solution of cuprocyanide ($[Cu(CN)_2]^-$), resulting in the deposition of 0.3745 g of Copper at the cathode. Calculate the exact industrial current efficiency. (Atomic mass Cu = 63.5)

Answer: C

💡 Solution & Explanation

$Q = 0.1 \times (2 \times 3600) = 720 C$. Cu is in +1 state. $Cu^+ + e^- \rightarrow Cu$. Theoretical moles = $720 / 96500 = 0.00746$ mol. Theoretical mass = $0.00746 \times 63.5 = 0.4737 g$. Efficiency = $(0.3745 / 0.4737) \times 100 \approx 79.0\%$.

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