JEE Main · 2026 · 05 Apr 2026 · Shift 1 · Hydrocarbons

A primary halide such as $n$-propyl chloride gives a primary carbocation with $\mathrm{AlC}{\mathrm{l}}_3$, and this rearranges by a 1,2-hydride shift to the more stable secondary isopropyl carbocation, which is the true electrophile; the chief product is isopropylbenzene (cumene), so statement A is wrong and statement B is right. The alkyl group introduced releases electron density and activates the ring to further attack, so repeated substitution cannot be avoided and statement C is correct. An electron-donating substituent raises the ring's electron density and so assists, rather than prevents, Friedel–Crafts alkylation, so statement D is wrong. The correct statements are B and C.