Question

What is carbocation intermediate?

Answer 1

Try to recall that there are many factors like dancing resonance, inductive effect, mesomeric effect, etc. on which the stability of carbocation. Now, by using this you can easily see that carbocation is a highly reactive intermediate species, they have one inherent positive charge and thus are always in the lookout for electrons, which tells us about their reactivity.

Complete answer:
A carbocation is an organic molecule, an intermediate that has a carbon atom bearing a positive charge and three bonds instead of four. Since the charged carbon atom does not satisfy the octet rule, it is unstable and therefore highly reactive. The intermediate species which possess a positively charged carbon are called carbocation or more commonly known as carbonium ions. In carbocation or carbonium ion, it has unhybridized $2p$ orbital and $sp^2$ hybridized carbon.
The bond angle in the carbocation is $120$ degrees. If we talk about carbocation rearrangement reaction, it can be defined as the movement of the carbocation from an unstable state to a more stable state of carbocation with the help of different structural organizational shifts within the molecule”. Alkyl carbocation is a carbocation that has an alkyl group. They are known to be the most common carbocation.
Rearrangement in carbocation happens only when alcohol is converted into several carbocations. The process or reaction is termed as rearrangement reaction to form carbocations. Carbocation has a positive charge on the carbon atom of a molecule which is connected by three more groups to form a complete structure. Rearrangement of carbocations is of two types: one is alkyl shift and another one is the hybrid shift.

Note:
Remember that carbocation intermediate is a common intermediate in $SN_1$ and $E_1$ reactions. Note that the first step in both reactions is the formation of a carbocation intermediate. A primary carbocation has one carbon group attached to the carbon bearing the positive charge. A secondary carbocation has two carbons attached to the carbon bearing the positive charge. A Tertiary carbocation has three carbons attached to the carbon bearing the positive charge.)