Question

A student conducted an electrochemical reaction using a copper electrode to reduce a solution containing Ag+ ions. The standard reduction potential for Ag+ is 0.80 V and the standard reduction potential for Cu2+ is 0.34 V. The student measured the cell potential to be 0.62 V. Calculate the overpotential of the reaction and determine if the reduction of Ag+ occurs spontaneously.

Answer 1

To determine the overpotential of the reaction, we first need to calculate the theoretical cell potential  Ecell  for the reaction. The cell potential can be calculated using the standard reduction potentials of the two half-reactions involved:Ecell = E cathode  - E anode In this case, the reduction of Ag+ ions is the cathode half-reaction, and the oxidation of Cu to Cu2+ is the anode half-reaction. So, we can plug in the standard reduction potentials:Ecell = 0.80 V - 0.34 V = 0.46 VNow that we have the theoretical cell potential, we can calculate the overpotential by comparing it to the measured cell potential:Overpotential = Measured cell potential - Theoretical cell potentialOverpotential = 0.62 V - 0.46 V = 0.16 VThe overpotential of the reaction is 0.16 V.To determine if the reduction of Ag+ occurs spontaneously, we can look at the sign of the cell potential. If the cell potential is positive, the reaction is spontaneous; if it is negative, the reaction is non-spontaneous.In this case, the theoretical cell potential  Ecell  is 0.46 V, which is positive. Therefore, the reduction of Ag+ ions occurs spontaneously.