Question

A halogen compound X (C\(_4\)H\(_9\)Br) on hydrolysis gave alcohol Y. The alcohol Y undergoes dehydration with 20\% H\(_3\)PO\(_4\) at 358 K. What is X?

• A. (CH\(_3\))\(_3\)CBr
• B. (CH\(_3\))\(_2\)CHCH\(_2\)Br
• C. CH\(_3\)CH\(_2\)CH\(_2\)CH\(_2\)Br
• D. CH\(_3\)CH(Br)CH\(_2\)CH\(_3\)

Hint:

Tertiary alkyl halides undergo SN1 reactions, forming stable carbocations, which easily dehydrate under acidic conditions.

Answer 1

The Correct Option is A

The halogen compound (CH\(_3\))\(_3\)CBr undergoes SN1 hydrolysis to form tertiary butanol. This tertiary butanol dehydrates with H\(_3\)PO\(_4\) to give 2-methylpropene, following a carbocation mechanism. Thus, (CH\(_3\))\(_3\)CBr is the correct halogen compound.