During the electrolysis of 0.1 M – CuSO4 solution using copper electrodes, a depletion of Cu^2+ occurs near the cathode with a corresponding excess near the anode, owing to inefficient stirring of the

Question

During the electrolysis of 0.1 M – CuSO4 solution using copper electrodes, a depletion of Cu^2+ occurs near the cathode with a corresponding excess near the anode, owing to inefficient stirring of the solution. If the local concentration of Cu^2+ near the anode and cathode are, respectively, 0.12 M and 0.08 M, the back EMF developed at 298 K is (log 1.5 = 0.18, 2.303RT/F = 0.06)

Prashant Kotian · Accepted Answer

Correct answer: B. This forms a concentration cell opposing the applied EMF. The back EMF is E = (0.06/2) * log([Cu^2+]_anode / [Cu^2+]_cathode). E = 0.03 * log(0.12 / 0.08) = 0.03 * log(1.5). Substituting log 1.5 = 0.18 gives E = 0.03 * 0.18 = 0.0054 V = 5.4 mV. Therefore, correct answer is B.

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