JEE Main · 2026 · 02 Apr 2026 · Shift 1 · Compounds Containing Nitrogen

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Consider the three aromatic molecules (P, Q and R) whose structures have been given below:

P. (see structure)

Q. (see structure)

R. (see structure)

The correct order regarding the reactivity of these compounds with

Ph - N \equiv N Cl^{(-)}

under optimum but (+) slightly acidic medium is:

(A)P $>$ Q $>$ R✓ Correct
(B) $R > P > Q$
(C) $R > Q > P$
(D)P $>$ R $>$ Q

Answer: (A)

Solution

Coupling with the benzenediazonium ion is an electrophilic substitution whose rate depends on how strongly the

- N (C H_{3})_{2}

lone pair can be fed into the ring. In P (N,N-dimethylaniline) the amino group lies coplanar with the ring and donates fully. In Q a single ortho methyl twists the

- N (C H_{3})_{2}

group partly out of the ring plane, weakening this donation by steric inhibition of resonance. In R two ortho methyls force the group almost perpendicular, nearly removing the donation. The reactivity therefore decreases in the order P > Q > R.

JEE Main · 2026 · 02 Apr 2026 · Shift 1 · Single correct option

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JEE Main · 2026 · 02 Apr 2026 · Shift 1 · Compounds Containing Nitrogen

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