$O{H^ - } + CHC{l_5} \rightleftharpoons HOH + :CC{l_3} \to C{l^ - } + :CC{l_2}$
${C_3}{H_7}OH\,\xrightarrow{{{H_2}S{O_4}}}X\,\xrightarrow{{B{r_2}}}\,Y\xrightarrow{{KOH}}Z$
$\begin{array}{*{20}{c}}
{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,O} \\
{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,||} \\
{C{H_2} = CH - C{H_2} - C - H}
\end{array} \to C{H_3} - C{H_2} - C{H_2} - C{H_2}OH$