The correct order of the rate of the reaction for the following reaction with respect to nucleophiles is: $\mathrm{CH}_{3} \mathrm{Br}+\mathrm{Nu}^{\Theta} \longrightarrow \mathrm{CH}_{3} \mathrm{Nu}+\mathrm{Br}^{\Theta}$

(D) ${ }^{-} \mathrm{OH}>\mathrm{PhO}^{-}>\mathrm{CH}_{3} \mathrm{COO}^{-}>\mathrm{ClO}_{4}^{-}$

(A) $\mathrm{PhO}^{-}>^{-} \mathrm{OH}>\mathrm{CH}_{3} \mathrm{COO}^{-}>\mathrm{ClO}_{4}^{-}$

(B) $\mathrm{ClO}_{4}^{-}>\mathrm{CH}_{3} \mathrm{COO}^{-}>{ }^{-} \mathrm{OH}>\mathrm{PhO}^{-}$

(C) $\mathrm{CH}_{3} \mathrm{COO}^{-}>\mathrm{PhO}^{-}>{ }^{-} \mathrm{OH}>\mathrm{ClO}_{4}^{-}$

JEE Main · 2026 · 21 Jan 2026 · Shift 2 · Haloalkanes and Haloarenes

The correct order of the rate of the reaction for the following reaction with respect to nucleophiles is:

CH_{3} Br + Nu^{Θ} ⟶ CH_{3} Nu + Br^{Θ}

(A) $PhO^{-} >^{-} OH > CH_{3} COO^{-} > ClO_{4}^{-}$
(B) $ClO_{4}^{-} > CH_{3} COO^{-} >^{-} OH > PhO^{-}$
(C) $CH_{3} COO^{-} > PhO^{-} >^{-} OH > ClO_{4}^{-}$
(D) $^{-} OH > PhO^{-} > CH_{3} COO^{-} > ClO_{4}^{-}$ ✓ Correct

Answer: (D)

Solution

The conversion of methyl bromide into

CH_{3} Nu

is a bimolecular substitution whose rate rises with the nucleophilic strength of the attacking anion, and for these oxygen nucleophiles nucleophilicity parallels basicity. Hydroxide is the strongest base and the best nucleophile; phenoxide is weakened by delocalisation of its charge into the aromatic ring; acetate is weakened further by delocalisation over two equivalent oxygens; and perchlorate, with its charge spread over four oxygens, is an extremely poor nucleophile. The rate therefore falls in the order

^{-} OH > PhO^{-} > CH_{3} COO^{-} > ClO_{4}^{-}

JEE Main · 2026 · 21 Jan 2026 · Shift 2 · Single correct option

Practise more: all JEE Main PYQs on Haloalkanes and Haloarenes →

JEE Main · 2026 · 21 Jan 2026 · Shift 2 · Haloalkanes and Haloarenes

Solution

More JEE Main questions on Haloalkanes and Haloarenes