$\underset{\text{Ethyl}\,\,\text{amine}}{\mathop{C{{H}_{3}}-C{{H}_{2}}-N{{H}_{2}}+C{{S}_{2}}}}\,\xrightarrow{HgC{{l}_{2}}}$ $\underset{\text{Ethyl}\,\,\text{isothiocyanate}}{\mathop{C{{H}_{3}}-C{{H}_{2}}-N=C=S}}\,\,+{{H}_{2}}S$
$C_2H_5-Br\overset{AgCN}{\rightarrow}A\overset{H_2/Ni}{\rightarrow}B$
Product $B$ is
In the above reaction, the structural formula of $(A), "X"$ and $"Y"$ respectively are :