A specimen of iron ore weighing 0.500g was dissolved in dilute sulphuric acid. The solution was titrated with 0.0200M potassium permanganate, 6.25cm3...

A specimen of iron ore weighing 0.500g was dissolved in dilute sulphuric acid. The solution was titrated with 0.0200M potassium permanganate, 6.25cm3 being required. The solution was reduced electrochemically (i.e. all the iron present was converted to Fe(II) and again titrated with potassium permanganate, 31.25cm3 being required. What are the percentages by weight of Fe(II) and Fe(III) in the ore?