Three different solutions of oxidizing agent ${\mathrm{KMnO}}_4,{\mathrm{K}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7$and ${\mathrm{I}}_2$ is titrated separately with $0.158 \mathrm{gm}$ of ${\mathrm{Na}}_2{\mathrm{S}}_2{\mathrm{O}}_3$.If molarity of each oxidizing agent is $0.1 \mathrm{M}$ and reactions are:

I ${\mathrm{MnO}}_4^{-}+{\mathrm{S}}_2{\mathrm{O}}_3^{2-}⟶{\mathrm{MnO}}_2+{\mathrm{SO}}_4^{2-}$

II ${\mathrm{CrO}}_7^{2-}+{\mathrm{S}}_2{\mathrm{O}}_3^{2-}⟶{\mathrm{Cr}}^{3+}+{\mathrm{SO}}_4^{2-}$

III ${\mathrm{I}}_2+{\mathrm{S}}_2{\mathrm{O}}_3^{2-}⟶{\mathrm{S}}_4{\mathrm{O}}_6^{2-}+{\mathrm{I}}^{-}$

Then: