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. 278
D. 156

Answer

A

Explanation

Mohr's salt is `(NH_(4))_(2)SO_(4)*FeSO_(4)*6H_(2)O` oxidation of ferrous oxide salts.
`5Fe^(2+)+MnO_(4)^(-)+8H^(+)to5Fe^(3+)+Mn^(2+)+4H_(2)O`
Total change in oxidation number of Fe
`=(+3)-(+2)=+1`
`therefore`Equivalent eight of Mohr's salt
`=("Molecular wt. of Mohr' salt")/(1)=(392)/(1)=392`