Question

number of moles in k2cr2o7 to oxidise two moles of ferrous oxalate in acidii medium

Answer 1

In acidic medium KMn(VII)O4 is reduced to Mn2+ by accepting 5 electrons, while Fe2+ by losing 1 electron gets oxidised to Fe3+,thus 1 mole of KMnO4 can oxidise 5 moles of FeSO4, which is clear by following balanced chemical equation

2 KMnO4 + 10 FeSO4 +8H2SO4 —->

K2SO4 +5 Fe2(SO4)3 +2MnSO4 +8 H2O.

Thus KMnO4 & FeSO4 react in the ratio 2:10 i.e. 1:5.