Among the following the most stable carbocation

Options

A. `CH_(3)-CH^(+)-CH_(3)`
B.
C.
D.

Answer

To determine the most stable carbocation among the given options, we will analyze each carbocation based on its structure and stability factors such as inductive effects, resonance, and aromaticity.

### Step-by-Step Solution:

1. **Identify the Structures**:
- **Option A**: CH3-CH^+-CH3 (Tertiary carbocation)
- **Option B**: A cyclic structure with a positive charge that can resonate (Aromatic compound)
- **Option C**: A cyclic structure with a positive charge that is anti-aromatic
- **Option D**: A structure with a positive charge on a bridgehead carbon (Bridgehead carbocation)

2. **Analyze Option A**:
- This is a tertiary carbocation where the positive charge is stabilized by three methyl groups through the +I (inductive) effect. The positive charge is localized, but the presence of three alkyl groups provides some stability.
- **Stability**: Moderate due to +I effect.

3. **Analyze Option B**:
- This structure is cyclic and can delocalize the positive charge through resonance. The positive charge can be spread over the entire ring, which stabilizes the carbocation significantly.
- Additionally, if it follows Huckel's rule (4n + 2 π electrons), it is aromatic, which is a key factor for stability.
- **Stability**: High due to resonance and aromaticity.

4. **Analyze Option C**:
- This structure is also cyclic but has a positive charge that is delocalized. However, it contains 4 π electrons, which makes it anti-aromatic. Anti-aromatic compounds are generally unstable due to the strain and lack of resonance stabilization.
- **Stability**: Low due to anti-aromaticity.

5. **Analyze Option D**:
- The positive charge is located on a bridgehead carbon. Carbocations at bridgehead positions are typically unstable due to steric hindrance and lack of effective resonance stabilization.
- **Stability**: Very low due to steric hindrance.

6. **Conclusion**:
- After analyzing all options, **Option B** is the most stable carbocation due to its aromatic nature and the ability to delocalize the positive charge effectively throughout the ring.

### Final Answer:
**The most stable carbocation among the given options is Option B.**