A galvanic cell is constructed from the following two half-reactions, each operating under standard conditions (25 °C, 1.0 M solutions, 1 atm gases).
Half-reaction 1: Ag+ + e⁻ → Ag(s) E° = +0.80 V
Half-reaction 2: Ni2+ + 2 e⁻ → Ni(s) E° = −0.25 V
(a) Write the balanced overall redox reaction that occurs when these two half-reactions are combined in a galvanic cell.
(b) Calculate the standard cell potential E°cell for the reaction written in part (a).
(c) Determine the value of the standard free-energy change ΔG° (in kJ mol⁻¹) for the overall reaction. Clearly state the number of moles of electrons transferred, include units in your answer, and indicate whether the sign of ΔG° is consistent with the spontaneity of the cell reaction.