Which amongst the following is the most stable carbocation :-

Options

A. `CH_(2)overset(oplus)CH_(2)`
B. `overset(oplus)CH_(2)`
C. `CH_(3) - undersetunderset(CH_(2))(|)C^(oplus)`
D. `CH_(3) - undersetunderset(CH_(3))(|)overset(oplus)CH`

Answer

To determine which carbocation is the most stable, we need to analyze the stability of different types of carbocations based on their structure and the effects of substituents.

### Step-by-Step Solution:

1. **Understand Carbocations**:
Carbocations are positively charged carbon species that are electron deficient. Their stability is influenced by the number of alkyl groups attached to the positively charged carbon. More alkyl groups typically lead to greater stability due to hyperconjugation and inductive effects.

2. **Identify the Types of Carbocations**:
The stability of carbocations can be classified as:
- **Primary (1°)**: A carbocation with one alkyl group attached to the positively charged carbon.
- **Secondary (2°)**: A carbocation with two alkyl groups attached.
- **Tertiary (3°)**: A carbocation with three alkyl groups attached.

3. **Analyze the Given Carbocations**:
Let's denote the carbocations as follows:
- **1° Carbocation (CH3-CH2+)**: One alkyl group.
- **2° Carbocation (CH3-CH+-CH3)**: Two alkyl groups.
- **3° Carbocation (CH3-C+-(CH3)2)**: Three alkyl groups.
- **Methyl Carbocation (CH3+)**: No alkyl groups.

4. **Evaluate Stability**:
- The **methyl carbocation** (CH3+) is the least stable because it has no alkyl groups to stabilize the positive charge.
- The **1° carbocation** (CH3-CH2+) is more stable than the methyl carbocation but less stable than the 2° and 3° carbocations.
- The **2° carbocation** (CH3-CH+-CH3) is more stable than the 1° carbocation due to the presence of two alkyl groups.
- The **3° carbocation** (CH3-C+-(CH3)2) is the most stable due to the presence of three alkyl groups, which provide maximum stabilization through hyperconjugation and inductive effects.

5. **Conclusion**:
Based on the analysis, the most stable carbocation among the options is the **3° carbocation**.

### Final Answer:
The most stable carbocation is the **3° carbocation**.