1-Phenylprop-1-ene, C6H5-CH=CH-CH3, is treated with HBr in the absence of peroxide. The major product is

JEE Advanced levelSingle correct optionDifficulty 3 of 3hx019

1-Phenylprop-1-ene, $C X_{6} H X_{5} - CH = CH - CH X_{3}$ , is treated with $HBr$ in the absence of peroxide. The major product is

Protonation of the double bond occurs at the carbon that gives the more stable carbocation. Adding

H X^{+}

to the

CH - CH X_{3}

carbon gives the benzylic cation

C X_{6} H X_{5} - CH X^{+} - CH X_{2} CH X_{3}

, stabilised by resonance with the ring. Bromide then gives

C X_{6} H X_{5} - CHBr - CH X_{2} CH X_{3}

, (1-bromopropyl)benzene.