If the molecular wt. of Na₂S₂O₃ and I₂ are M₁ and M₂ respectively, then what will be the equivalent wt. of Na₂S₂O₃ and I₂ in the following reaction?  

In hypo two sulphur atoms per molecule is undergoing change in oxidation state.

Valency factor (n-factor) =$\left|\left[\left(2\times 2.5\right)-\left(2\times 2\right)\right]\right|=1$

${\mathrm{E}}_{{\mathrm{Na}}_2{\mathrm{S}}_2{\mathrm{O}}_3}=\frac{{\mathrm{M}}_1}{1}={\mathrm{M}}_1$

Valency factor of I₂ = $\left|\left[2\left(-1\right)-2\left(0\right)\right]\right|=2$

${\mathrm{E}}_{{\mathrm{I}}_2}=\frac{{\mathrm{M}}_2}{2}$