JEE Main · 2019 · 10 Apr 2019 · Shift 1 · Hydrocarbons

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The increasing order of the reactivity of the following compounds towards electrophilic aromatic substitution reaction is:

(I) (see structure)
(II) (see structure)
(III) (see structure)

(A)(III) $<$ (I) $<$ (II)✓ Correct
(B)(III) $<$ (II) $<$ (I)
(C)(II) $<$ (I) $<$ (III)
(D)(I) $<$ (III) $<$ (II)

Answer: (A)

Solution

In electrophilic aromatic substitution, electron-donating groups activate the ring and electron-withdrawing groups deactivate it. In chlorobenzene the chlorine is weakly deactivating through its

- I

effect; in toluene the methyl group is activating; in acetophenone the

- COCH X_{3}

group is strongly deactivating by both

- R

and

- I

. Reactivity rises from acetophenone, to chlorobenzene, to toluene.

JEE Main · 2019 · 10 Apr 2019 · Shift 1 · Single correct option

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