properties and uses of Potassium permanganate (KMnO4)

Properties of Potassium permanganate (KMnO₄)


1. Potassium permanganate (KMnO₄): Action of Heat

Potassium permangante on strong heating gives potassium manganate, manganese dioxide and oxygen.

2 KMnO₄ ----------> K₂MnO₄ + MnO₂ + O₂


2. Oxidising properties of Potassium permanganate (KMnO₄)

Potassium permanganate is a powerful oxidizing agent in alkaline or acidic solution. The relevant half reactions are:

1. Alkaline medium (pH > 7)

MnO₄^- + 2H₂O + 3 e^- ----------> MnO₂ + 4OH^-


2. Acidic medium (pH <7)

MnO₄^- + 8H⁺ + 5e^- ----------> Mn²⁺ + 4H₂O



A few important oxidizing reactions of Potassium permanganate (KMnO₄)


1. In acidic medium potassium permanganate oxidizes green ferrous salts to yellow ferric salts

MnO₄^- + 8H⁺ + 5Fe²⁺ ----------> 5Fe³⁺ + Mn²⁺ + 4H₂O


2. in acidic medium potassium permanganate oxidizes oxalic acid or oxalate salts to CO₂ and water

2 MnO₄^- + 16H⁺ + 5 C₂O₄^2- -------------> 2 Mn²⁺ + 10 CO₂ + 8 H₂O


3. In acidic medium potassium permanganate oxidizes nitrites to nitrate.


2 MnO₄^- + 6 H⁺ + 5 NO₂^- -------------> 2 Mn²⁺ + 5 NO₃^- + 3 H₂O


4. In acidic medium potassium permanganate oxidises iodides to iodine.

2 MnO₄^- + 16 H⁺ + 1 OI^- ----------> 2 Mn²⁺ + 8 H₂O + 5 I₂


5. In alkaline medium potassium permanganate oxidizes iodides to iodates .

2 MnO₄^- + H₂O + I^- ------------> IO₃^- + 2MnO₂ + 2 OH^-


To know more about Potassium permanganate (KMnO4) visit http://entrancechemistry.blogspot.com/2012/08/preparation-of-potassium-permanganate.html