$\begin{array}{*{20}{c}} {\,\,O} \\ {\,||} \\ {C{H_3} - C - C{H_3}} \end{array}$ $ + \,{H_2}O$
$[Figure]$ $\xrightarrow[{(ii){H_2}O}]{{(i)\,{C_2}{H_5}MgBr}}A\xrightarrow{{HCl}}B$