JEE Main Chemistry question

Which one of the following pairs gives effervescence with aq. NaHCO₃? (Repeated-pattern question analogous to Q236, with a fresh set of acyl compounds)

(A)An acid chloride and an anhydride (both hydrolyze to liberate a free carboxylic acid, releasing CO₂ with bicarbonate)Correct
(B)Two esters (neither hydrolyzes spontaneously under these mild conditions)
(C)A ketone and an ester
(D)Two amides

Answer: (A)

Solution

As established for this reaction type, only compounds that readily generate a free carboxylic acid under these mild aqueous conditions (acid chlorides and anhydrides, both of which hydrolyze rapidly even without added acid/base catalyst) will liberate CO₂ with bicarbonate; esters, ketones and amides are all far too

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Question ID VK-149522