Question

In the following reactions,


The major products (A) and (C) are respectively:

• A.
• B.
• C.
• D.

Answer 1

The correct option is B



In the first reaction, dehydration is governed by Saytzeff rule which gives a more substituted alkene product. Here, the secondary carbocation formed undergoes 1, 2 hydride shift and give more stable tertiary carbocation which further undergo beta elimination to give major product (A). Thus, 2- Methyl but-2-ene is the major product.

Compound (A) now reacts with HBr in the absence of peroxide.
This reaction is governed by Markovnikov rule according to which when an unsymmetrical alkene undergo hydrohalogenation, the negative part of the addendum (adding molecule) gets attached to that doubly bonded C which posses lesser number of hydrogen atoms. when an unsymmetrical reagent. Thus, in above case, 2-Methyl 2-bromo butane will be the major product.