Question

ASSERTION-Addition of HCl to 3-methyl-1-butene gives 2-chloro-2-methyl butane as the major product.
REASON-Rearrangement of carbocation to more stable carbocation leads to the formation of the major product.
A)Both Assertion and Reason are correct and the reason is the correct explanation for the assertion.
B)Both Assertion and Reason are correct and the reason is not the correct explanation for assertion
C)The assertion is correct but the reason is incorrect
D)Both Assertion and Reason are incorrect

Answer 1

To answer this question, you should recall the concept of rearrangement reactions. A rearrangement reaction involves migration of an H atom or a larger molecular fragment within a relatively short-lived intermediate product.

Complete Step by step solution:
We know that these rearrangement reactions are called sigma-tropic processes as they involve breaking of a bond and movement of a migrating group. The assertion in our question states that the addition of HCl to 3-methyl-1-butene gives 2-chloro-2-methyl butane as the major product. It is true as given in the below reaction:

The reason given is that rearrangement will take place, of the carbocation to a more stable carbocation which leads to the formation of a product that is major. We can see that 2-chloro-3-methyl butane will become a major product in absence of rearrangement of carbocation as shown in the above mechanism. So, both Assertion and Reason are true and the Reason is the correct explanation of Assertion.
Therefore, we can conclude that the correct answer to this question is option A.

Note: You should know other types of rearrangement reactions too. These include: Curtius reaction, Claisen rearrangement, Beckmann rearrangement, Hoffman rearrangement, pericyclic rearrangement and photochemical rearrangements.