Out of the given isomeric hydrocarbons which will undergoes rearrangement reaction in acidic medium?

Options

A.
B.
C.
D.

Answer

To determine which isomeric hydrocarbons will undergo rearrangement reactions in acidic medium, we need to analyze the stability of the carbocations formed during the reaction. Here’s a step-by-step solution:

### Step 1: Identify the Isomeric Hydrocarbons
Assume we have four isomeric alkenes (let's label them A, B, C, and D). Each of these alkenes will react with an acid (H+) to form a carbocation.

### Step 2: Apply Markovnikov's Rule
According to Markovnikov's rule, when H+ adds to an alkene, it will attach to the carbon that has more hydrogen atoms already attached, leading to the formation of a more stable carbocation.

### Step 3: Analyze Each Isomer
1. **Isomer A**:
- When H+ is added, it forms a tertiary carbocation (3°).
- Tertiary carbocations are stable and do not undergo rearrangement.
- **Conclusion**: No rearrangement.

2. **Isomer B**:
- This is a symmetrical alkene.
- H+ addition leads to a secondary carbocation (2°).
- A secondary carbocation can rearrange to form a more stable tertiary carbocation via a 1,2-hydride shift.
- **Conclusion**: Rearrangement is possible.

3. **Isomer C**:
- Upon addition of H+, a secondary carbocation is formed.
- Similar to Isomer B, this secondary carbocation can rearrange to a more stable tertiary carbocation.
- **Conclusion**: Rearrangement is possible.

4. **Isomer D**:
- H+ addition forms a tertiary carbocation (3°).
- Since it is already stable, it will not undergo rearrangement.
- **Conclusion**: No rearrangement.

### Step 4: Final Conclusion
Based on the analysis:
- Isomers B and C can undergo rearrangement reactions in acidic medium.
- Isomers A and D do not undergo rearrangement.

### Summary
The isomeric hydrocarbons that will undergo rearrangement reactions in acidic medium are **Isomer B and Isomer C**.