The products A and B in the following reactions, respectively are $\mathrm{A} \stackrel{\mathrm{Ag}-\mathrm{NO}_{2}}{\longrightarrow} \mathrm{CH}_{3}-\mathrm{CH}_{2}-\mathrm{CH}_{2}-\mathrm{Br} \xrightarrow{\mathrm{AgCN}} \mathrm{B}$

(D) $\mathrm{CH}_{3}-\mathrm{CH}_{2}-\mathrm{CH}_{2}-\mathrm{NO}_{2}, \mathrm{CH}_{3}-\mathrm{CH}_{2}-\mathrm{CH}_{2}-\mathrm{NC}$

(A) $\mathrm{CH}_{3}-\mathrm{CH}_{2}-\mathrm{CH}_{2}-\mathrm{ONO}, \mathrm{CH}_{3}-\mathrm{CH}_{2}-\mathrm{CH}_{2}-\mathrm{NC}$

(B) $\mathrm{CH}_{3}-\mathrm{CH}_{2}-\mathrm{CH}_{2}-\mathrm{ONO}, \mathrm{CH}_{3}-\mathrm{CH}_{2}-\mathrm{CH}_{2}-\mathrm{CN}$

(C) $\mathrm{CH}_{3}-\mathrm{CH}_{2}-\mathrm{CH}_{2}-\mathrm{NO}_{2}, \mathrm{CH}_{3}-\mathrm{CH}_{2}-\mathrm{CH}_{2}-\mathrm{CN}$

JEE Main · 2025 · 28 Jan 2025 · Shift 1 · Haloalkanes and Haloarenes

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The products A and B in the following reactions, respectively are

A ⟶ Ag - NO_{2} CH_{3} - CH_{2} - CH_{2} - Br AgCN B

(A) $CH_{3} - CH_{2} - CH_{2} - ONO, CH_{3} - CH_{2} - CH_{2} - NC$
(B) $CH_{3} - CH_{2} - CH_{2} - ONO, CH_{3} - CH_{2} - CH_{2} - CN$
(C) $CH_{3} - CH_{2} - CH_{2} - NO_{2}, CH_{3} - CH_{2} - CH_{2} - CN$
(D) $CH_{3} - CH_{2} - CH_{2} - NO_{2}, CH_{3} - CH_{2} - CH_{2} - NC$ ✓ Correct

Answer: (D)

Solution

Silver nitrite is largely ionic, and when it reacts with a primary alkyl halide it is the nitrogen end of the nitrite ion that displaces the halide, giving the nitroalkane as the major product:

C H_{3} - C H_{2} - C H_{2} - B r A g N O_{2} C H_{3} - C H_{2} - C H_{2} - N O_{2}

(A). Silver cyanide, in contrast, is covalent, and here carbon stays bonded to silver while the nitrogen lone pair acts as the nucleophile, so the major product with an alkyl halide is the isocyanide rather than the nitrile:

C H_{3} - C H_{2} - C H_{2} - B r A g C N C H_{3} - C H_{2} - C H_{2} - N C

(B). A is propyl nitro compound and B is propyl isocyanide.

JEE Main · 2025 · 28 Jan 2025 · Shift 1 · Single correct option

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JEE Main · 2025 · 28 Jan 2025 · Shift 1 · Haloalkanes and Haloarenes

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