Explanation:
\(C{{H}_{3}}-C\equiv N\,+\,C\overline{{{H}_{3}}}M{{g}^{+}}Br\to \) $\begin{matrix}
C{{H}_{3}}-C=N-MgBr \\
|\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, \\
C{{H}_{3}}\,\,\,\,\,\,\,\, \\
\end{matrix}$ $\xrightarrow{Hydrolysis}$ $C{{H}_{3}}-CO-C{{H}_{3}}+N{{H}_{3}}+$ $Mg\,<\,\begin{matrix}
Br \\
OH \\
\end{matrix}$
