\(R - C{H_2} - C{H_2} - CN\, \xrightarrow[{{H_3}{O^ + }}]{{HO{H^ - }}}\,R - C{H_2} - C{H_2} - COOH\)
$\begin{array}{*{20}{c}}
{{C_2}{H_5}MgBr + {H_2}C - C{H_2}\xrightarrow{{{H_2}O}}} \\
{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\backslash \,\,\,\,/} \\
{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,O}
\end{array}A$
$RCH_2OH + PCC [ C_5H_5NH^+ ClCrO^-_3] \to$