In the following reaction, hydrazine is oxidized to $N_2$

$N_2{H}_4+O{H}^{-}\underset{ }{\overset{ }{\to }}{N}_2+H_{2}O+e^{-}$

The equivalent mass of $N_2{H}_4$ (hydrazine) is ____

In $N_2{H}_4$ oxidation state of nitrogen is + 2. 

In $N_2$ oxidation state of nitrogen is ‘0’

Now as 2 atoms of N in $N_2{H}_4$ is converting from +2 to 0. So n factor =4 

Equivalent mass = $\frac{molecularmass}{nature}=\frac{32}{4}=8$