B24 Reactions of Sodium with Solutions of Permanganate in Ammonia and in Water

Description
Potassium permanganate dissolved in liquid ammonia is reduced by sodium. When sodium is added to an aqueous solution of potassium permanganate, the sodium reacts with the water instead of the permanganate. The comparison illustrates the advantage of using nonaqueous solvents for certain reactions.

Equation
MnO₄^- + Na --> Na⁺ + MnO₄²^-(green)

MnO₄²^- + 2 Na + 2 NH₃ --> MnO₂(brown ppt) + 2 Na⁺ + 2 OH^- + 2 NH₂^-

2 H₂O + 2 Na --> 2 NaOH + H₂

Reference
G. P. Pass and H. Sutcliffe,"Practical Inorganic Chemistry",Chapman and Hall LTD., London,Great Britain, (1968).