Write the chemical equations for the preparation of KMnO4 from MnO2.
Preparation of potassium permanganate: Potassium permanganate is prepared by the fusion of MnO2 (pyrolusite) with potassium hydroxide and an oxidizing agent like KNO3 to form potassium manganate (green mass), which disproportionate in a neutral or acidic solution to form permanganate.