Question

Preparation of potassium permanganate from pyrolite ore

Answer 1

Answer:

Pottassium Permanganate (KMnO4) is prepared fromPyrolusite ore (MnO2). The finely powdered Pyrolusite ore(MnO2) is fused with an alkali metal hydroxide like KOH in the presence of air or an oxidizing agent like KNO3 to give the dark green potassium Manganate (K2MnO4). Potassium manganate disproportionate in a neutral or acidic solution to give potassium permanganate.

2 MnO2 + 4 KOH + O2 ----------> 2K2MnO4 + 2H2O

3 MnO42- + 4H+ ------------> 2MnO4- + MnO2 + 2H2O

Commercially potassium permanganate is prepared by the alkaline oxidative fusion of Pyrolusite ore (MnO2) followed bythe electrolytic oxidation of manganate (4) ion.

2 MnO2 + 4KOH + O2 -----------> 2K2MnO4 + 2H2O

MnO42- ------(electrolytic oxidation)----> MnO4- + e-