Acidified Potassium Permanganate
The molecular weight of KMnO4 is 158.04 g/mol with tetrahedral structure. The oxidation of iron can be done in the presence of potassium permanganate to form an insoluble manganese dioxide and iron oxide which can be removed by filtration. It has dark colour purple solid which form pink colour solution in water.
The colour of solution depends on the concentration of compound in solution. This compound has very useful for various applications such as for the treatment of water in pharmaceutical manufacture. It is used to oxidize Fe, Mn, H2S and ‘As’ impurities.
The treatment of water with it also improves taste and odour. It is used as a pre-oxidant for disinfection by-product control. KMnO4 can help to produce high quality water which can easily meet drinking water standards. It mainly involves in the oxidation of functional groups like aromatic side chains to RCOOH, organic sulphides to sulphones which is used to produce antibiotics and tranquilizers.
The oxidation reaction of KMnO4 is effected by the pH of the solution as Mn can exist from 2+ to 7+ oxidation state. Out of that Mn7+ is the most potent oxidation state in both acid and alkaline medium. This oxidation process is widely used in organic synthesis such as phase transfer catalysis. For example the oxidation of ferrous sulphate with acidified potassium permanganate results the formation of ferric sulphate with manganese sulphate and potassium sulphate. The oxidation reaction can be written as given below;
We cannot write one formula for acidified potassium permanganate as it is a mixture, not a pure compound. Manganese exists in 7+ oxidation state in potassium permanganate which is reduced to colourless or pink Mn2+ ion in acidic medium. The ionic reaction can be written as given below;