Manganese may play an important role in chemical cycles in the oceans. Two reactions involving manganese (in acid solution) are the reduction of nitrate ions (to NO) with Mn²⁺ ions and the oxidation of ammonium ions (to N₂) with MnO₂.
(a) Write balanced chemical equations for these reactions (in acid solution).
(b) Calculate E° cell for the reactions. (One half-reaction potential you need is for the reduction of N₂ to NH₄⁺, E° = −0.272 V.)