# 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????

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 $M n {O}_{2}$ which is a brown compound, insoluble in water.
When you add ${H}_{2} S {O}_{4}$ the dioxide decomposes into oxygen, water and manganese II sulfate
$2 M n {O}_{2} + 2 {H}_{2} S {O}_{4} \rightarrow 2 M n S {O}_{4} + {O}_{2} + 2 {H}_{2} O$