8H+ + 5Fe2+ + MnO – → 5Fe3+ + Mn2+ + 4H2O
For 25 ml,
meq of Fe2+ = meq of MnO –
= 12.5 × 0.03 × 5
For 250 ml,
m moles of Fe2+ = \(12.5 \times 0.03 \times 5 \times \frac{250}{25}\)
moles of Fe2+ = \(\frac{18.75}{1000}\)mol
= 18.75 × 10–3 mol
= 1.875 × 10–2 mol
x = 1.875
Weight of Fe2+ = 1.875 × 10–2 × 56 = 1.05 g
% purity of Fe2+ y = 18.75%