5.5g of a mixture of FeSO4⋅7H2O and Fe2(SO4)3⋅9H2O required 5.4mL of 0.1NKMnO4 solution for complete oxidation. Calculate the gram mole of hydrated ferric sulphate in the mixture. (At. mass H=1,O=16,S=32,Fe=56).
Open in App
Solution
Only FeSO4⋅7H2O will be oxidised by KMnO4. Mol. mass of FeSO4⋅7H2O=278 As the conversion involves one electron, Fe2+→Fe3++e− The eq. mass of FeSO4⋅7H2O=2781=278 5.4mL of 0.1NKMnO4 ≡5.4mL of 0.1NFeSO4⋅7H2O solution Amount of FeSO4⋅7H2O=0.1×2781000×5.4=0.15g Amount of Fe2(SO4)3⋅9H2O=(5.5−0.15)=5.35g Mol. mass of Fe2(SO4)3⋅9H2O=562 No. of g moles of Fe2(SO4)3⋅9H2O=MassMol.mass =5.35562=0.00952 =9.52×10−3.