Each of the following spontaneous redox reactions occurs in a voltaic cell.
a. Write the half-reaction that occurs at the anode.
b. Write the half-reaction that occurs at the cathode.
c. Calculate E°cell.

1. 2MnO₄⁻(aq) + 3V(s) + 8H⁺(aq) → 2MnO₂(s) + 3V²⁺(aq) + 4H₂O(l)
2. 2Br⁻(aq) + 2Mn³⁺(aq) → Br₂(l) + 2Mn²⁺(aq)
3. 2Zn²⁺(aq) + 4OH⁻(aq) + N₂