Chemistry - Electrochemistry Question with Solution | TestHub

In an analytical determination of arsenic, a solution containing arsenious acid, ${\mathrm{H}}_3{\mathrm{AsO}}_3,\mathrm{KI}$ and a small amount of starch is electrolysed. The electrolysis produces free ${\mathrm{I}}_2$ from ${\mathrm{I}}^{-}$ions and the ${\mathrm{I}}_2$ immediately oxidizes the arsenious acid to hydrogen arsenate ion, ${\mathrm{HAsO}}_4{}^{2-}$.

I₂ + H₃AsO₃ + H₂O → 2I⁻ + HAsO₄²⁻ + 4H⁺

When the oxidation of arsenic is complete, the free iodine combines with the starch to give a deep blue color. If, during a particular run, it takes $96.5s$ for a current of $1.68mA$ to give an endpoint (indicated by the blue color), how many grams of arsenic are present in the solution? (As = $75$)