Question 62: Consider the following reaction and identify the product (P).
\mathrm{CH_3-CH(CH_3)-CH(OH)-CH_3} reacts with \mathrm{HBr}.
Answer: Option (3)
Explanation:
The given alcohol is \mathrm{3\!-\!methylbutan\!-\!2\!-\!ol},
which is a secondary alcohol.
On reaction with \mathrm{HBr}, the alcohol undergoes substitution via the \mathrm{S_N1} mechanism.
First, the \mathrm{-OH} group is protonated and leaves as water,
forming a secondary carbocation.
This carbocation rearranges by a hydride shift to form a more stable tertiary carbocation.
Finally, the bromide ion attacks the tertiary carbocation to form
\mathrm{2\!-\!bromo\!-\!2\!-\!methylbutane}.
Hence, the correct product corresponds to option (3).