Question

How will you obtain pure potassium permanganate (KMnO₄) crystals from its ore, pyrolusite? Give the steps involved and the reactions. 

Answer 1

Potassium permanganate crystals (KMnO₄) from pyrolusite:
It involves two steps
Step 1: Conversion of pyrolusite into potassium manganate

\[\ce{2MnO2 + 4KOH + O2 ->[Fuse] 2K2MnO4 + 2H2O}\]

Step 2: Conversion of potassium manganate into potassium permanganate (By isolation)

\[\ce{\underset{(Aqueous solution)}{K2MnO4 + Cl2} -> 2KMnO4 + 2KCl}\]

On crystallisation, the crystals of KMnO₄ appear, which are separated and dried.