Asked in Premeth Test 22 — Carboxylic Acids, Alcohols and Phenols (24 March 2025) 2025Moderate

Which of the following derivatives cannot be prepared directly from carboxylic acid?

Correct answer: B. Acid amide

  • A. Acid halide
  • B. Acid amide
  • C. Ester
  • D. Acid anhydride

Explanation

The direct reaction of a carboxylic acid with ammonia results in an acid-base reaction, forming an ammonium carboxylate salt. This salt must then be heated to dehydrate it to form the acid amide. The other derivatives can be formed in a single step.

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About Carboxylic Acid Derivatives

Carboxylic acid derivatives include acid halides, acid anhydrides, esters and amides, formed by replacing the hydroxyl group of a carboxylic acid. Their nomenclature, structures, preparation, hydrolysis and relative reactivity are linked through nucleophilic acyl substitution, which differs from the nucleophilic addition reactions of aldehydes and ketones.

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550 free Carboxylic Acids MCQs from Chemistry, each with the correct answer and an explanation. Unlimited attempts, no account needed.

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