Question

$3C{H}_{3}C{H}_{2}C{H}_{2}COOH+PC{l}_3\stackrel{△}{\to }3A+E$
$A+RCO{O}^{-}\to B$
$A+ROH\to C$
$A+RN{H}_2\to D$
$B,C$ and $D$ respectively are:

• A. acid anhydride, ester, acid amide
• B. acid anhydride, acid amide, ester
• C. acid anhydride, ester, ether
• D. acid anhydride, ester and acid halide

Answer 1

Answer: (A)

acid anhydride, ester, acid amide

The compound $\left(A\right)$ is an acid. The compounds $B,C$ and $D$ are an acid anhydride, ester, and acid amide respectively.
The reactions are as shown.
$3C{H}_{3}C{H}_{2}C{H}_{2}COOH+PC{l}_3\underset{△}{\overset{}{\to }}3\underset{A}{C{H}_{3}C{H}_{2}C{H}_{2}COCl}+\underset{E}{H_{3}P{O}_3}$
$\underset{A}{C{H}_{3}C{H}_{2}C{H}_{2}COCl}+RCO{O}^{-}\to \underset{B}{C{H}_{3}C{H}_{2}C{H}_{2}COOCOR}+C{l}^{-}$
$\underset{A}{C{H}_{3}C{H}_{2}C{H}_{2}COCl}+ROH\to \underset{C}{C{H}_{3}C{H}_{2}C{H}_{2}COOR}+HCl$
$\underset{A}{C{H}_{3}C{H}_{2}C{H}_{2}COCl}+RN{H}_2\to \underset{D}{C{H}_{3}C{H}_{2}C{H}_{2}CONHR}+HCl$