How many moles of `KMnO_(4)` are required to oxidise one mole of ferrous oxalate in acidic medium ?

Explanation

Ferrous oxalate is a dual reducing agent. In acidic medium `MnO_(4)^(-)` oxidises ferrous ion to ferric ion and oxalate ion to `CO_(2)`. Thus balanced equation for the reaction between the permanganate ion and ferrous oxalate is 
`3MnO_(4)^(-)("3 mole")+5FeC_(2)O_(4)("5 mole")+24H^(+)rarr 3Mn^(2+)+5Fe^(3+)+10CO_(2)+12H_(2)O`
Thus one mole of `KMnO_(4)` can oxidise 1.67 moles of ferrous oxalate.