Chemistry - Redox Reactions Question with Solution | TestHub

A mixture containing $\mathrm{A}{\mathrm{s}}_2{\mathrm{S}}_3$ and $\mathrm{A}{\mathrm{s}}_2{\mathrm{S}}_5$ requires 20 ml of 0.05 N iodine for titration. The resulting solution is then acidified and excess of $\mathrm{KI}$ was added. The liberated iodine required 0.992 g hypo, $\mathrm{N}{\mathrm{a}}_2{\mathrm{S}}_2{\mathrm{O}}_3\cdot 5{\mathrm{H}}_2\mathrm{O}$, for complete reaction. The reactions are $\mathrm{A}{\mathrm{s}}_2{\mathrm{S}}_3$ + $2{\mathrm{I}}_2$ + $2{\mathrm{H}}_2\mathrm{S}$ $\to$ $\mathrm{A}{\mathrm{s}}_2{\mathrm{S}}_5$ + $4{\mathrm{H}}^{+}$ + $4{\mathrm{I}}^{-}$; $\mathrm{A}{\mathrm{s}}_2{\mathrm{S}}_5$ + $4{\mathrm{H}}^{+}$ + $2{\mathrm{I}}^{-}$ $\to$ $\mathrm{A}{\mathrm{s}}_2{\mathrm{S}}_3$ + $2{\mathrm{I}}_2$ + $2{\mathrm{H}}_2\mathrm{S}$. The mole per cent of $\mathrm{A}{\mathrm{s}}_2{\mathrm{S}}_3$ in the original mixture is (As = 75)