Assertion (A): Acetyl chloride is more reactive towards nucleophiles than ethyl acetate. Reason (R): The chlorine atom donates its lone pair into the carbonyl group by resonance more effectively than the ester oxygen does.

ABoth A and R are true and R is the correct explanation of A
BBoth A and R are true but R is not the correct explanation of A
CA is true but R is false
DA is false but R is true

Answer: C

A is true. R is false: the 3p lone pair of Cl overlaps poorly with the 2p orbital of carbon, so resonance donation is weak, while the ester oxygen (2p-2p) donates effectively. The reactivity of the acid chloride comes from this weak donation, together with the strong

- I

effect of Cl and the excellent leaving group

Cl X^{-}

. Hence option C.

Practice Organic Reaction Mechanisms I: Nucleophiles and Carbonyl Addition More on Nucleophilic acyl substitution of carboxylic acid derivatives

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Assertion (A): Acetyl chloride is more reactive towards nucleophiles than ethyl acetate. Reason (R): The chlorine atom donates its lone pair into the carbonyl group by resonance more effectively than the ester oxygen does.

Answer: C

More questions on Nucleophilic acyl substitution of carboxylic acid derivatives