Conjugate acid $\mathrm{NH}_{3}$ is obtained by addition of $\mathrm{H}^{+}$ ion to the base $\mathrm{NH}_{2}^{-}$is
$\underset{\text { Base }}{\mathrm{NH}_{2}^{-}}+\mathrm{H}^{+} \longrightarrow \underset{\begin{array}{c}
\text { Conjugate } \\
\text { acid }
\end{array}}{\mathrm{NH}_{3}}$