a
\(\mathop {C{H_3} - C \equiv CH}\limits_{(propyne)} \) \(+\) \(H_2O\) \(\xrightarrow {H_2SO_4,\,HgSO_4}\) \(\begin{array}{*{20}{c}}
{\,\,\,OH} \\
{|\,\,} \\
{C{H_3} - C = C{H_2}}
\end{array}\) \(\rightleftharpoons \) \(\mathop {\begin{array}{*{20}{c}}
{}&O&{}&{} \\
{}&{||}&{}&{} \\
{C{H_3} - }&{C - }&{C{H_3}}&{} \\
{}&{}&{}&{}
\end{array}}\limits_{(Acetone)} \)