The number of moles of oxalate ions oxidised by one mole of `MnO_(4)^(-)` ion in acidic medium is :

Explanation

Equivalents of `C_(2)O_(4)^(2-)`=equivalents of `MnO_(4)^(-)`
x(mole)`xx2=1xx5`
`(.:. "v.f. of " C_(2)O_(4)^(2-)=2(4-3)=2 " and v.f. of " MnO_(4)^(-)=1(7-2)=5)`.
`x=(5)/(2)` mole of `C_(2)O_(4)^(2-)` ions.