The standard cell potential E°(cell) is +0.77 V for the redox reaction 2 Fe³⁺(aq) + H₂(g) → 2 H⁺(aq) + 2 Fe²⁺(aq). Determine E° for the half-reaction Fe³⁺(aq) + e⁻ → Fe²⁺(aq).

Answer 1

Since Fe3+ is being reduced, we know that it is the cathode.

Hydrogen has a standard potential of zero, so we don't need to take Eoxidized into account with the formula Ecell = Ereduced - Eoxidized

Therefore, Ecell = Ereduced - 0.

Thus, .77 V = Ereduced.

E for the half reaction of Fe3+ + e- -> Fe2+ is .77 V.