Question

The equivalent weight of Mohrs salt is:

• A. 56
• B. 158
• C. 278
• D. 392

Answer 1

Answer: (D)

The molecular weight of Mohrs salt $(FeS{O}_4\cdot {(N{H}_4)}_{2}S{O}_4\cdot 6H_{2}O)$ = 56+2 (32 + 64) + 2 (14 + 4) + 6 (18) = 56 +192 + 36 +108 = 392 $\therefore$ Equivalent weight of reductant $=\frac{\text{Mol}\text{.wt}\text{.}}{\text{increase}\text{in}\text{O}\text{.N}\text{.}}=\frac{392}{1}=392$ ( $\because$ $F{e}^{2+}$ changes into $F{e}^{3+}$ in its reactions)