Class 12 Chemistry D and F Block Elements Preparation of Pottassium Permanganate

Preparation of Pottassium Permanganate (KMnO4)

Pottassium Permanganate (KMnO4) is a dark purple solid consisting of two ions: a potassium ion (K⁺) and a permanganate ion (MnO− 4). It is a strong oxidizing agent and also possess medication properties due to which it is extensively used to clean wounds and in dermatitis.

  • Fusion of powdered Pyrolusite ore (MnO2) with an alkali metal hydroxide like KOH in the presence of air or an oxidizing agent like KNO3 leads to the formation of dark green potassium Manganate (K2MnO4) which disproportionate either in a neutral or acidic medium and results in the formation of potassium permanganate.

2 MnO2 + 4 KOH + O2 --> 2K2MnO4 + 2H2O
3 MnO42- + 4H+  --> 2MnO4- + MnO2 + 2H2O

  • Potassium permanganate is commercially prepared by an alkaline oxidative fusion of Pyrolusite ore (MnO2) and again by the electrolytic oxidation of manganate (4) ion.

2 MnO2 + 4KOH + O2 --> 2K2MnO4 + 2H2O
MnO42- + (electrolytic oxidation)  --> MnO4- + e-

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