3-Methylbut-1-ene, CH2=CH-CH(CH3)2, reacts with HBr (no peroxide). The major product is

JEE Main levelSingle correct optionDifficulty 2 of 3hc028

3-Methylbut-1-ene, $CH X_{2} = CH - CH (CH X_{3}) X_{2}$ , reacts with $HBr$ (no peroxide). The major product is

Protonation gives the secondary cation

CH X_{3} - CH X^{+} - CH (CH X_{3}) X_{2}

, which undergoes a 1,2-hydride shift to the more stable tertiary cation

CH X_{3} CH X_{2} - C X^{+} (CH X_{3}) X_{2}

. Bromide captures it to give 2-bromo-2-methylbutane as the major product.