$\begin{array}{*{20}{c}}
{Ph - CH - CH - CHO\xrightarrow[\Delta ]{{{K_2}C{O_3}}}} \\
{\,\,\,\,\,\,\,\,\,\,\,|\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,|\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,} \\
{\,\,\,\,\,\,Br\,\,\,\,\,\,\,\,\,\,Br\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,}
\end{array}$
$(I)\,\,CH_2 =CH-CH_2Cl$ $(II)\,\,CH_2=CH-CH(CH_3) Cl$
$(III)\,\,CH_2 =C(CH_3)CH_2Cl$ $(IV)\,\, CH_3CH = CH-CH_2Cl$
$\begin{array}{*{20}{c}}
{C{H_3}\,\,\,} \\
{|\,\,\,\,\,\,\,\,} \\
{C{H_3} - C - CHC{H_3}} \\
{\,|\,\,\,\,\,\,\,\,\,\,|} \\
{\,\,H\,\,\,\,\,\,\,Br}
\end{array}$ $\xrightarrow{{C{H_3}OH}}$