25.0 mL of a ferrous sulphate solution requires 21.5 mL of 0.0200 M KMnO4 in acidic medium. The molarity of the Fe^2+ solution is:

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$25.0 mL$ of a ferrous sulphate solution requires $21.5 mL$ of $0.0200 M$ $KMnO X_{4}$ in acidic medium. The molarity of the $Fe X^{2 +}$ solution is:

MnO X_{4} X^{-} + 5 Fe X^{2 +} \to

products, so milliequivalents match:

25.0 \times M \times 1 = 21.5 \times 0.0200 \times 5 = 2.15

M = 2.15/25.0 = 0.0860 M