$\underset{1}{\mathop{\begin{matrix}
O\,\,\,\,\,\,\,\,\,\,\,\, \\
||\,\,\,\,\,\,\,\,\,\,\,\,\, \\
C{{H}_{3}}COCHC{{H}_{3}} \\
\end{matrix}}}\,$ $\underset{2}{\mathop{\begin{matrix}
\,\,\,\,O \\
\,\,\,\,|| \\
C{{H}_{3}}CCl \\
\end{matrix}}}\,$ $\underset{3}{\mathop{\begin{matrix}
O\,\,\,\,\,\,\,\,\, \\
||\,\,\,\,\,\,\,\,\, \\
C{{H}_{3}}CNHC{{H}_{3}} \\
\end{matrix}}}\,$
$(ii)$ $CH _{3} COOH$
$(iii) $ $C _{6} H _{5} COOH$
$(iv)$ $CH _{3} CH _{2} COOH$
$ PK _ {a} $ મૂલ્યનો યોગ્ય ક્રમ કયો છે ?
ઉપરની પ્રક્રિયામાં '$A$' શોધો