A voltaic cell is constructed with two silver-silver chloride electrodes, where the half-reaction is AgCl(s) + e^- → Ag(s) + Cl^- (aq) E° = +0.222 V
The concentrations of chloride ion in the two compartments are 0.0222 mol L^-1 and 2.22 mol L^-1, respectively. The cell emf is ________ V.

Question

Quizplus · Accepted Answer

The Nernst equation gives the cell emf:
Ecell = E°cell - (RT/nF)ln(Q)
where E°cell is the standard cell potential, R is the gas constant, T is the temperature in Kelvin, n is the number of electrons transferred in the half-reaction, F is Faraday's constant, and Q is the reaction quotient. For this cell, n = 1 and Q = [Ag+][Cl-]/[AgCl] in the anode compartment and [AgCl]/[Ag+][Cl-] in the cathode compartment.
Plugging in the given values:
Ecell = 0.222 V - (0.0257 V/K)(298 K/1)(ln[(0.0222 M)(2.22 M)/(1 M)]) = 0.118 V
Therefore, the best choice is B.

A Voltaic Cell Is Constructed with Two Silver-Silver Chloride Electrodes