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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 C2O42- -------------> 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

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