Styrene undergo following reactions in acidic medium

The various intermadite formed are :

MnO_(4)^(2-) undergoes disproportionation reaction in acidic medium but MnO_(4)^(-) does not .Give reason.

The hydrolysis of ethyl acetate in acidic medium is a reaction of:

MnO_(4)^(2-) undergoes disproportionation reaction in acidic medium but MnO_(4)^(-) does not. Given reason.

MnO_(4)^(2-) undergoes disproportionation reaction in acidic medium but MnO_(4)^(-) does not. Given reason.