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


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#