$\begin{array}{*{20}{c}}
{\,\,\,\,\,\,C{H_3}} \\
| \\
{C{H_3} - C - OH} \\
| \\
{\,\,\,\,\,\,C{H_3}}
\end{array}\, \to \begin{array}{*{20}{c}}
{\,\,\,C{H_3}} \\
| \,\,\,\,\\
{C{H_3} - {C^ \oplus } - O{H^ - }} \\
| \,\,\,\,\\
{C{H_3}}
\end{array}$
$3^o$ કાર્બોનિયમ આયન
ફિનોલ $,$ $p-$ મિથાઇલફિનોલ $,$ $ m-$ નાઇટ્રોફિનોલ અને $p-$ નાઇટ્રોફિનોલ
$C{H_3}C{H_2}OH\xrightarrow{{P + {I_2}}}A\xrightarrow[{ether}]{{Mg}}B\xrightarrow{{HCHO}}C\xrightarrow{{{H_2}O}}D$