Potassium permanganate oxidises oxalic acid in suphuric acid medium to give potassium sulphate, manganous sulphate, carbondioxide and water.

Explanation

(a) The skeleton equation is written as
`KMnO_(4) +H_(2)C_(2)O_(4)+H_(2)SO_(4) to K_(2)SO_(4)+MnSO_(4)+CO_(2)+H_(2)O`
(b) Focusing on the oxidation numbers
`overset(+1)(K) overset(+7)(Mn) overset(-2)(O_(4))+overset(+1)(H_(2)) overset(+3)(C_(2)) overset(-2)(O_(4))+overset(+1)(H_(2)) overset(+6)(S) overset(-2)O_(4) to overset(+1)(K_(2)) overset(+6)(S) overset(-2)(O_(4)) + overset(+2)(Mn) overset(+6)(S) overset(-2)(O_(4))+overset(+4) (C) overset(-2)(O_(2)) +overset(+1)(H_(2)) overset(-2)(O)`
(c) Location atoms undergoing change in oxidation numbers.
`KM overset(+7)(n)O_(4)+H_(2) overset(+3)(C_(2))O_(4) to Mn overset(+2)(SO_(4))+C overset(+4)(CO_(2))`
(d) Determine the change in oxidation numbers
(e) Cris- crossing these changes in oxidation numbers
`2KMnO_(4)+5H_(2)C_(2)O_(4) to MnSO_(4)+CO_(2)`
(f) Balancing the atoms other than hydrogen and oxygen
`2KMnO_(4)+5H_(2)C_(2)O_(4)+3H_(2)SO_(4) to K_(2)SO_(4)+2MnSO_(4)+10CO_(2)+H_(2)O`
(g) Balancing the atoms hydrogen and oxygen
`2KMnO_(4)+5H_(2)C_(2)O_(4)+3H_(2)SO_(4) to K_(2)SO_(4)+2MnSO_(4)+10CO_(2)+8H_(2)O`
This is the balanced equations.