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 M and 2.22 M, respectively. The cell emf is __________ V.

Question

Quizplus · Accepted Answer

The Nernst equation for the given half-reaction is Ecell = E° - (0.0592/n) log Q, where n is the number of electrons transferred and Q is the reaction quotient. In this case, n is 1 since only 1 electron is transferred. The reaction quotient can be calculated as Q = [Ag+]/[Cl-]. At standard conditions, both compartment have [Ag+] = [Cl-] = 1 M, so Q = 1. At non-standard conditions, the anode compartment has [Cl-] = 0.0222 M and the cathode compartment has [Cl-] = 2.22 M, so Q = 0.01. Thus, Ecell = 0.222 - (0.0592/1) log 0.01 = 0.118 V. The correct answer is B.

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