The major product of the following chemical reaction is: $$\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CN} \xrightarrow{\stackrel{\text{1) } \mathrm{H}_{3} \mathrm{O}^{+}, \Delta}{\text{2) } \mathrm{SOCl}_{2}}} \text{3) } \mathrm{Pd} / \mathrm{BaSO}_{4}, \mathrm{H}_{2} \text{ ?}$$

(B) $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CHO}$

(A) $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{OH}$

(C) $(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CO})_{2} \mathrm{O}$

(D) $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{3}$

JEE Main · 2021 · 25 Feb 2021 · Shift 1 · Aldehydes Ketones and Carboxylic Acids

The major product of the following chemical reaction is:

CH_{3} CH_{2} CN 2) SOCl_{2} 1) H_{3} O^{+}, Δ 3) Pd / BaSO_{4}, H_{2} ?

(A) $CH_{3} CH_{2} CH_{2} OH$
(B) $CH_{3} CH_{2} CHO$ ✓ Correct
(C) $(CH_{3} CH_{2} CO)_{2} O$
(D) $CH_{3} CH_{2} CH_{3}$

Answer: (B)

Solution

Acid hydrolysis of the nitrile replaces the

- CN

group by

- COOH

, giving propanoic acid. Thionyl chloride converts the acid to propanoyl chloride, the gaseous by-products leaving the mixture. Hydrogen over palladium poisoned with barium sulfate is the Rosenmund condition: the poisoned catalyst is weak enough to reduce the acid chloride but not the aldehyde it produces, so the reduction halts at that stage. The major product is propanal,

C H_{3} C H_{2} CHO

JEE Main · 2021 · 25 Feb 2021 · Shift 1 · Single correct option

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JEE Main · 2021 · 25 Feb 2021 · Shift 1 · Aldehydes Ketones and Carboxylic Acids

Solution

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