
Product of the reaction is methyl benzoate \(\begin{array}{*{20}{c}}
{O\,\,\,\,\,\,\,\,\,\,\,\,} \\
{||\,\,\,\,\,\,\,\,\,\,\,\,\,} \\
{Ph - C - \mathop O\limits^{18} - C{H_3}}
\end{array}\)

${C_2}{H_5}I\xrightarrow{{alc. KOH}}X\xrightarrow[{CC{l_4}}]{{B{r_2}}}Y\,\xrightarrow{{KCN}}Z\xrightarrow{{{H_3}{O^ + }}}A$

