Question

Which is most reactive towards nucleophilie substitution among acid derivatives?

• A. ${\left(RCO\right)}_{2}O$
• B. $RCOX$
• C. $RCO{NH}_2$
• D. $RCOOR$

Answer 1

The correct option is B $RCOX$

The leaving group in each case has an atom with lone pair of electrons adjacent to the carbonyl group. The compounds, therefore, exist as resonance hybrids and become stable. The greater the stabilisation, lower is the reactivity. Due to lower stabilisation, the acid halides are more reactive.