Question

The equivalent weight of Mohr’s salt, $FeSO_4 . (NH_4)_2SO_{4}.6 H_2O$ is equal to

• A. its molecular weight
• B. atomic weight
• C. half-its molecular weight
• D. one-third its molecular weight.

Answer 1

Answer: (A)

$\overset{\text{ +2}}{ Fe}SO_4 \rightarrow \overset{\text{ +3}}{Fe }_2(SO_4)_3$
$FeSO_4$ present in Mohr’s salt gets converted into $Fe_2(SO_4)_3$. This is a one-electron change and hence Eq. wt. of Mohr’s salt is equal to its Mol. wt.