How is potassium permanganate `(KMnO_(4))` prepared from `MnO_(2)` ? Write the equations.

Explanation

Potassium Permanganate prepared by fusion of `MnO_2` with an alkali metal hydroxide and an oxidising agent like `KNO_3`. This produces the dark green `K_2 MnO_4` which disproportionates in a neutral or acidic solution to give permanganate.
` 2MnO_2 + 4KOH + O_2 to 2K_2MnO_4 + 2H_2O`
`3MnO_(4)^(2-) + 4H^(+) to 2MnO_(4)^(-) + MnO_(2) + 2H_2O`