$(I)$ $PhCOOH$
$(II)$ $o-\, NO_2C_6H_4COOH$
$(III)$ $P-\, NO_2C_6H_4COOH$
$(IV)$ $m-\, NO_2C_6H_4COOH$
નીચે આપેલાં ક્રમ માંથી સાચો ક્રમ કયો હશે ?
$\underset{1}{\mathop{\begin{matrix}
O\,\,\,\,\,\,\,\,\,\,\,\, \\
||\,\,\,\,\,\,\,\,\,\,\,\,\, \\
C{{H}_{3}}COCHC{{H}_{3}} \\
\end{matrix}}}\,$ $\underset{2}{\mathop{\begin{matrix}
\,\,\,\,O \\
\,\,\,\,|| \\
C{{H}_{3}}CCl \\
\end{matrix}}}\,$ $\underset{3}{\mathop{\begin{matrix}
O\,\,\,\,\,\,\,\,\, \\
||\,\,\,\,\,\,\,\,\, \\
C{{H}_{3}}CNHC{{H}_{3}} \\
\end{matrix}}}\,$