When i add KMnO4 into an unsaturated carboxylic acid the color of KMnO4 changes to brown and when i added few drops of H2SO4 into this brown solution the brown color disapears. how this occur kindly help me????

1 Answer
Jan 12, 2016

See below

Explanation:

When you add the potassium permanganate to an unsaturated carboxylic acid in a neutral medium, the permanganate saturates the acid and is reduced to manganese dioxide MnO_2 which is a brown compound, insoluble in water.

When you add H_2SO_4 the dioxide decomposes into oxygen, water and manganese II sulfate

2MnO_2 + 2H_2SO_4 rarr 2MnSO_4 + O_2 + 2H_2O