$\begin{array}{*{20}{c}}
O\\
{||}\\
{C{H_3} - C - C{H_3}}
\end{array}$ $ + \begin{array}{*{20}{c}}
{C{H_2}OH}\\
{\,\,\,\,|\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,}\\
{C{H_2}OH}
\end{array}$ $\overset{HCl}{\longleftrightarrow}$ ?
$C{H_2} = C{H_2}\xrightarrow{{{O_2}/Ag}}X\xrightarrow{{473\,{\kern 1pt} K}}Y$