JEE Advanced 2018 — Paper 2 — Question 23

To measure the quantity of $\mathrm{MnCl}_{2}$ dissolved in an aqueous solution, it was completely converted to $\mathrm{KMnO}_{4}$

using the reaction, $\mathrm{MnCl}_{2}+\mathrm{K}_{2} \mathrm{~S}_{2} \mathrm{O}_{8}+\mathrm{H}_{2} \mathrm{O} \rightarrow \mathrm{KMnO}_{4}+\mathrm{H}_{2} \mathrm{SO}_{4}+\mathrm{HCl}$ (equation not

balanced). Few drops of concentrated HCl were added to this solution and gently warmed. Further, oxalic acid

( 225 mg ) was added in portions till the colour of the permanganate ion disappeared. The quantity of $\mathrm{MnCl}_{2}$ (in

mg ) present in the initial solution is $\_\_\_\_$

(Atomic weights in $\mathrm{g} \mathrm{mol}^{-1}: \mathrm{Mn}=55, \mathrm{Cl}=35.5$ )