
$C{H_3}C{H_2}C \equiv CH\, + \,HCl\, \to \,B\,\xrightarrow{{HI}}C$

$\begin{array}{*{20}{c}}
{Ph - CH - CH - CHO\xrightarrow[\Delta ]{{{K_2}C{O_3}}}} \\
{\,\,\,\,\,\,\,\,\,\,\,|\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,|\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,} \\
{\,\,\,\,\,\,Br\,\,\,\,\,\,\,\,\,\,Br\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,}
\end{array}$

