The amount of arsenic pentasulphide that can be obtained when $35.5\;g$ arsenic acid is treated with excess $H_2S$ in the presence of conc. $HCl$ ( assuming 100% conversion) is

Question

$\begin{array}{1 1}(1)0.50\;mol \\ (2) 0.25\;mol \\ (3) 0.125\;mol \\ (4) 0.333\;mol \end{array} $