Question

Acid anhydride undergoes nucleophilic substitution at a faster rate than ethyl acetate primarily because :

• A. ethoxide is better leaving group than acetate.
• B. acetate is better leaving group than ethoxide.
• C. the anhydride is less sterically hindered than the ester.
• D. the ester is less sterically hindered than an anhydride.

Answer 1

Answer: (B)

acetate is better leaving group than ethoxide.

Acetate is a resonance stabilized, weaker base, hence better-leaving group than ethoxide ion so acid anhydride undergo nucleophilic substitution at a faster rate than ethyl acetate.

Hence, the correct option is B.