11.86 When 3-methylbutan-2-ol is treated with HBr, the following reaction takes place: Give a mechanism for this reaction. (Hint : The secondary carbocation formed in step II rearranges to a more stable tertiary carbocation by a hydride ion shift from 3rd carbon atom.

11.86 

The first step in the mechanism of the given reaction is protonation of the alcohol followed by loss of water to give a 2⁰ carbocation.

2. The next step is a rearrangement of the 2⁰ carbocations formed in the above step is less stable it rearranges by a 1,2-hydride shift to form more stable 3°