Question

The following carbocation rearranges to:

A)

B)

C)

D)

Answer 1

Hint: We know that carbocation is a positively charged carbon atom. The carbocation with the least partial positive charge is more stable. This is because the charge is distributed among neighbouring carbons. Higher the charge density on the carbon atom, more unstable is the carbocation.

Complete step by step solution:
We are given a carbocation in which the positively charged carbon atom is attached to two alkyl groups.
When a positively charged carbon atom is attached to two alkyl groups it is known as a secondary carbocation.
Thus, the carbocation given to us is a secondary carbocation.
All carbocations have a unique property of rearrangement. The carbocations rearrange themselves to form a more stable carbocation.
Now, the given secondary carbocation will rearrange itself to form a more stable carbocation i.e. a tertiary carbocation. The rearrangement of secondary carbocation is as follows:

In the rearranged carbocation, we can see that the positively charged carbon atom is attached to three alkyl groups.
When a positively charged carbon atom is attached to three alkyl groups it is known as a tertiary carbocation.
Thus, the rearranged carbocation is a tertiary carbocation which is more stable.

Thus, the correct option is (D).

Note: When a carbon atom carrying a positive charge is attached to only one alkyl group it is known as a primary carbocation. When a carbon atom carrying a positive charge is attached to two other alkyl groups it is known as a secondary carbocation. When a carbon atom carrying a positive charge is attached to three other alkyl groups it is known as a tertiary carbocation. A tertiary carbocation is more stable than the secondary carbocation which is more stable than the primary carbocation.