Consider the following reactions. From these reactions which reaction will give carboxylic acid as a major product? (A) $\mathrm{R}-\mathrm{C} \equiv \mathrm{N} \xrightarrow[\text { mild condition }]{\text { (i) } \mathrm{H}^{+} / \mathrm{H}_{2} \mathrm{O}}$ (B) $\mathrm{R}-\mathrm{MgX} \xrightarrow[\text { (ii) } \mathrm{H}_{3} \mathrm{O}^{+}]{\text {(i) } \mathrm{CO}_{2}}$ (C) $\mathrm{R}-\mathrm{C} \equiv \mathrm{N} \xrightarrow[\text { (ii) } \mathrm{H}_{3} \mathrm{O}^{+}]{\text {(i) } \mathrm{SnCl}_{2} / \mathrm{HCl}}$ (D) $\mathrm{R} \cdot \mathrm{CH}_{2} \cdot \mathrm{OH} \xrightarrow{\mathrm{PCC}}$ (E) (see structure) Choose the correct answer from the options given below :

JEE Main · 2025 · 02 Apr 2025 · Shift 2 · Aldehydes Ketones and Carboxylic Acids

Consider the following reactions. From these reactions which reaction will give carboxylic acid as a major product?
(A)

R - C \equiv N (i) H^{+} / H_{2} O mild condition

(B)

R - MgX (i) CO_{2} (ii) H_{3} O^{+}

(C)

R - C \equiv N (i) SnCl_{2} / HCl (ii) H_{3} O^{+}

(D)

R \cdot CH_{2} \cdot OH PCC

(E) (see structure)

Choose the correct answer from the options given below :

(A)A and D only
(B)A, B and E only
(C)B, C and E only
(D)B and E only✓ Correct

Answer: (D)

Solution

A carboxylic acid results only where the final product carries the

- COOH

group. A Grignard reagent adds to carbon dioxide and, after acid work-up, gives a carboxylic acid, so that pathway qualifies. In the benzoyl chloride route the acid chloride is first reduced by

H X_{2} / Pd - BaSO X_{4}

(Rosenmund reduction) to benzaldehyde, which bromine water then oxidises to benzoic acid, so that route qualifies too. Mild acid hydrolysis of a nitrile stops at the amide; treatment with

SnCl X_{2} / HCl

followed by hydrolysis is the Stephen reduction, which gives an aldehyde; and PCC oxidation of a primary alcohol gives an aldehyde. The reactions yielding a carboxylic acid as the major product are the Grignard addition to carbon dioxide and the Rosenmund reduction followed by bromine-water oxidation.

JEE Main · 2025 · 02 Apr 2025 · Shift 2 · Single correct option

Practise more: all JEE Main PYQs on Aldehydes Ketones and Carboxylic Acids →

JEE Main · 2025 · 02 Apr 2025 · Shift 2 · Aldehydes Ketones and Carboxylic Acids

Solution

More JEE Main questions on Aldehydes Ketones and Carboxylic Acids