In basic medium CrO_4^2- oxidises S_2 O_3^2- to form SO_4^2- and itself changes into Cr ( OH )_4^-. The volume of 0.154 M CrO_4^2- required to react…

In basic medium $\displaystyle \mathrm{CrO}_4{ }^{2-}$ oxidises $\displaystyle \mathrm{S}_2 \mathrm{O}_3{ }^{2-}$ to form $\displaystyle \mathrm{SO}_4{ }^{2-}$ and itself changes into $\displaystyle \mathrm{Cr}(\mathrm{OH})_4{ }^{-}$. The volume of $\displaystyle 0.154 \mathrm{~M} \mathrm{~CrO}_4{ }^{2-}$ required to react with $\displaystyle 40$ mL of $\displaystyle 0.25 \mathrm{~M} \mathrm{~S}_2 \mathrm{O}_3{ }^{2-}$ is \_\_\_\_ mL. (Rounded-off to the nearest integer)