Explanation:
$\underset{Ethyl\,\,acetate}{\mathop{\begin{matrix}
\,O \\
\,|| \\
C{{H}_{3}}C-C-{{C}_{2}}{{H}_{5}} \\
\end{matrix}}}$ $+\,C{{H}_{3}}MgBr\,\to $ $\begin{array}{*{20}{c}}
{\begin{array}{*{20}{c}}
{\,\,\,\,\,\,\,\,\,\,O - MgBr} \\
{|\,\,\,\,\,\,\,\,\,\,\,\,\,\,}
\end{array}} \\
{C{H_3} - C - O - {C_2}{H_5}} \\
{|\,\,\,\,\,\,\,\,\,\,\,\,\,\,} \\
{C{H_3}\,\,\,\,\,\,\,}
\end{array}$ $\xrightarrow[{ - \,Mg\, < \,\begin{array}{*{20}{c}}
{Br} \\
{OH}
\end{array}}]{{ + \,{H_2}O}}$ $\begin{array}{*{20}{c}}
{\begin{array}{*{20}{c}}
{\,\,\,\,\,\,\,OH} \\
|
\end{array}} \\
{C{H_3} - C - OH} \\
| \\
{\,\,\,\,\,\,\,\,\,C{H_3}}
\end{array}$ $\xrightarrow{{ - \,{H_2}O}}$ $\begin{array}{*{20}{c}}
O \\
{||} \\
{C{H_3} - C - C{H_3}}
\end{array}$ $\xrightarrow[{C{H_3}MgBr}]{{Excess\,\,of}}$ $\begin{array}{*{20}{c}}
{\begin{array}{*{20}{c}}
{C{H_3}\,\,} \\
{|\,\,\,\,\,\,\,\,}
\end{array}} \\
{C{H_3} - C - OMgBr} \\
{\,\,|\,\,\,\,\,\,\,\,\,\,} \\
{C{H_3}\,}
\end{array}$ $\xrightarrow{{{H_2}O}}$ $\mathop {\begin{array}{*{20}{c}}
{\begin{array}{*{20}{c}}
{\,\,\,\,\,C{H_3}} \\
|
\end{array}} \\
{C{H_3} - C - OH} \\
{\,\,|} \\
{\,\,\,\,\,\,\,\,\,\,C{H_{3.}}}
\end{array}}\limits_{t\, - \,Butanol} $
