The equivalent mass of ${\mathrm{MnSO}}_4$ is half its molecular mass when it is converted to :

When mnso4 is transformed to, its equivalent weight is half of its molecular weight. The equivalent weight will be equal to the molecular weight if the valency equals 2. As a result, the valency factor for the conversion of ${\mathrm{MnSO}}_4$to ${\mathrm{MnO}}_2$is 2, and the equivalent weight of ${\mathrm{MnSO}}_4$is equal to half of its molecular weight.

${\mathrm{MnSO}}_4⟶{\mathrm{MnO}}_2$