${KMnO}_{4}+{FeSO}_{4} \rightarrow {Fe}_{2}\left({SO}_{4}\right)_{3}+{Mn}^{2+}$

${n}=5 \quad {n}=1$

(Equivalents of ${KMnO}_{4}$ reacted $)=$ (Equivalents of ${FeSO}_{4}$ reacted $)$

$\Rightarrow(5 \times x \times 10\, {ml})=1 \times 0.1 \times 10\, {ml}$

$\Rightarrow {x}=0.02\, {M}$

Molar mass of ${KMnO}_{4}=158\, {gm} / {mol}$

$\Rightarrow \text { Strength }=({x} \times 158)=3.16\, {~g} / \ell$