The major product of which of the following reaction is not obtained by rearrangement reaction?
(A)(see structure)
(B)(see structure)✓ Correct
(C)(see structure)
(D)(see structure)
Answer: (B)
Solution
Treatment of benzene with n-propyl chloride and anhydrous aluminium chloride forms a primary propyl cation that rearranges by a hydride shift to the more stable isopropyl cation, giving isopropylbenzene; n-hexane with aluminium chloride and hydrogen chloride isomerises through carbocation rearrangement to 2-methylpentane; and neopentyl alcohol under acid forms a primary cation that undergoes a methyl shift to a tertiary cation before losing a proton to give 2-methyl-2-butene. Each of these major products arises through a rearrangement. The dehydration of tert-butyl alcohol, by contrast, proceeds through the already tertiary carbocation, which simply loses a proton to give 2-methylpropene, so its major product is formed without any rearrangement.
JEE Main · 2026 · 08 Apr 2026 · Shift 2 · Single correct option
