Question

In the following reaction (unbalanced), equivalent weight of $As_{2}S_{3}$ is related to molecular weight M by
$As_{2}S_{3} +H+NO^{-}_{3} \to NO +H_{2}O +AsO^{3-}_{4} +SO^{2-}_{4}$

• A. $\frac{M}{2}$
• B. $\frac{M}{4}$
• C. $\frac{M}{28}$
• D. $\frac{M}{24}$

Answer 1

Answer: (C)

$As_{2}S_{3} \to AsO^{3-}_{4} + 3SO_{4}^{2-}$
O.N $2As = + 6\,\,\,\,\,2\times5\,\,\,\,\,\, 3\times6$
$3s = - 6\,\,\,\, =10 \,\,\,\,\,=18$
Net = - Total = 28 Net change = 28
Thus, equivalent mass of $As_{2}O_{3} = \frac{M}{28}$