3-Methylbutan-2-yl cation, CH3-CH^+-CH(CH3)2, rearranges by a single 1,2-shift to:

JEE Main levelSingle correct optionDifficulty 2 of 3g3013

3-Methylbutan-2-yl cation, $CH X_{3} - CH X^{+} - CH (CH X_{3}) X_{2}$ , rearranges by a single 1,2-shift to:

A hydride on the neighbouring tertiary carbon shifts to the cationic carbon. The positive charge moves to the tertiary carbon, giving

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

(2-methylbutan-2-yl cation). The other options either are primary or have the wrong carbon count.