Prioritize the highest acidity of carboxylic acid in the following
Correct answer: C. Chloro-ethanoic acid
- A. Propanoic acid
- B. Ethanoic acid
- C. Chloro-ethanoic acid
- D. 2-Methyl Propanoic acid
Explanation
Carboxylic acids are most acidic organic compounds. Resonance stabilization of carboxylate ion allows the negative charge to be delocalised among the two electronegative oxygen atoms. Addition of adjacent electron withdrawing substituents increases acidic character. Hence substituted chloroethanoic acid will be more acidic than simple ethanoic acid and others.Acidic character can also be hinted from the pKa values as follows:ethanoic acid pKa= 4.7propanoic acid pKa= 4.9chloroethanoic acid pKa= 2.92-meethyl propanoic acid pKa= 4.9
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About Reactivity of Carboxylic Acids
Carboxylic acids show acidic behaviour because their carboxylate ions are resonance-stabilised, and electron-withdrawing groups can change their strength. Reactions include neutralisation, esterification, formation of acid chlorides and amides, reduction, decarboxylation and substitution at the acyl carbon, which differs from the reactions of phenols.
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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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