The descending order of acidity for the following carboxylic acid is : A. $\mathrm{CH}_{3} \mathrm{COOH}$ B. $\mathrm{F}_{3} \mathrm{C}-\mathrm{COOH}$ C. $\mathrm{ClCH}_{2}-\mathrm{COOH}$ D. $\mathrm{FCH}_{2}-\mathrm{COOH}$ E. $\mathrm{BrCH}_{2}-\mathrm{COOH}$ Choose the correct answer from the options given below :

(D) B $>$ D $>$ C $>$ E $>$ A

(A) D $>$ B $>$ A $>$ E $>$ C

(B) E $>$ D $>$ B $>$ A $>$ C

(C) B $>$ C $>$ D $>$ E $>$ A

JEE Main · 2023 · 08 Apr 2023 · Shift 2 · Aldehydes Ketones and Carboxylic Acids

The descending order of acidity for the following carboxylic acid is :
A.

CH_{3} COOH

F_{3} C - COOH

ClCH_{2} - COOH

FCH_{2} - COOH

BrCH_{2} - COOH

Choose the correct answer from the options given below :

(A)D $>$ B $>$ A $>$ E $>$ C
(B)E $>$ D $>$ B $>$ A $>$ C
(C)B $>$ C $>$ D $>$ E $>$ A
(D)B $>$ D $>$ C $>$ E $>$ A✓ Correct

Answer: (D)

Solution

Acid strength rises as the group on the alpha carbon withdraws electrons more strongly and stabilises the carboxylate ion. Trifluoroacetic acid carries three fluorine atoms and shows the strongest withdrawal, so it is the most acidic. Among the monohalogenated acids the inductive withdrawal falls in the order fluorine, then chlorine, then bromine, so fluoroacetic acid is stronger than chloroacetic acid, which is stronger than bromoacetic acid. Acetic acid has only an electron-releasing methyl group and is the weakest. The descending order of acidity is trifluoroacetic acid, fluoroacetic acid, chloroacetic acid, bromoacetic acid, acetic acid.

JEE Main · 2023 · 08 Apr 2023 · Shift 2 · Single correct option

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JEE Main · 2023 · 08 Apr 2023 · Shift 2 · Aldehydes Ketones and Carboxylic Acids

Solution

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