This oxidation-reduction reaction in acidic solution is spontaneous:
5 Fe2+(aq) + MnO4 -(aq) + 8 H+(aq)¡ 5 Fe3+(aq) + Mn2+(aq) + 4 H2O(l)
A solution containing KMnO4 and H2SO4 is poured into one beaker, and a solution of FeSO4 is poured into another. A salt bridge is used to join the beakers. A platinum foil is placed in each solution, and a wire that passes through a voltmeter connects the two solutions.
(a) Sketch the cell, indicating the anode and the cathode, the direction of electron movement through the external circuit, and the direction of ion migrations through the solutions.
(b) Sketch the process that occurs at the atomic level at the surface of the anode.
(c) Calculate the emf of the cell under standard conditions.
(d) Calculate the emf of the cell at 298 K when the concentrations are the following: pH = 0.0, [Fe2+] = 0.10 M, [MnO4-] = 1.50 M, [Fe3+] = 2.5 × 10-4 M, [Mn2+] = 0.001 M.