$X\xrightarrow{{{\text{Bromination}}}}Y\xrightarrow{{NaN{O_2} + HCl}}Z\mathop {\xrightarrow{{{\text{Boiling}}}}}\limits_{{C_2}{H_5}OH} {\text{Tribromobenzene}}$
$\xrightarrow{{SOC{l_2}}}B\xrightarrow{{N{H_3}}}C\xrightarrow[{B{r_2}}]{{NaOH}}D$


$C{{H}_{3}}CN+2H\underset{\text{Ether}}{\mathop{\xrightarrow{HCl}}}\,X\underset{{{H}_{2}}O}{\mathop{\xrightarrow{\text{Boiling}}}}\,Y;$ the term $Y$ is: