The formula mass of Mohr's salt is 392. The iron present in it is oxidised by `KMnO_(4)` in acid medium. The equivalent mass of Mohr's salt is :

Options

A. 392
B. 31.6
C. 287
D. 156

Answer

A

Explanation

Mohr’s salt is `(NH_(4))_(2) SO_(4).FeSO_(4) .6H_(2)O` oxidation of ferrous salts .
`5Fe^(2+) + MnO_(4)^(-) + 8H^(+) to 5Fe^(3+) + Mn^(2+) + 4H_(2)O`
Total change in oxidation number of Fe ` = (+3) - (+2) = +1`
`therefore ` Equivalent weight of Mohr’s salt
` = ("molecular wt. of Mohr' s salt")/(1) = (392)/(1) = 392`