Most stable carbanion among the following is

Options

A. `CH_(3)-CH_(2)^(-)`
B.
C. `CH_(3)-underset(CH_(3))underset(|)overset(CH_(3))overset(|)(C^(-))`
D. All of these

Answer

To determine the most stable carbanion among the given options, we need to analyze the structure of each carbanion and the effects of the surrounding groups on the stability of the negative charge.

### Step-by-Step Solution:

1. **Identify the Carbanions:**
- Option A: CH3CH2- (ethyl carbanion)
- Option B: CH3CH2CH-CH3 (butyl carbanion)
- Option C: CH3C-CH3 (isopropyl carbanion)
- Option D: All of these

2. **Understand Carbanion Stability:**
- Carbanions are negatively charged species where the negative charge is localized on a carbon atom. The stability of carbanions is influenced by the electron-donating or electron-withdrawing effects of substituents attached to the carbon atom bearing the negative charge.

3. **Evaluate Inductive Effects:**
- Alkyl groups are electron-donating due to their +I (inductive) effect. The more alkyl groups attached to the carbon with the negative charge, the greater the electron density at that carbon, which can destabilize the carbanion.

4. **Analyze Each Option:**
- **Option A (CH3CH2-):** There is one alkyl group (ethyl), which has a minimal +I effect. This carbanion is relatively stable.
- **Option B (CH3CH2CH-CH3):** There are two alkyl groups (butyl), which exert a stronger +I effect than option A, making it less stable than option A.
- **Option C (CH3C-CH3):** There are three alkyl groups (isopropyl), which exert the strongest +I effect among the three options, making it the least stable carbanion.
- **Option D (All of these):** This option suggests that all carbanions are equally stable, which is incorrect based on the analysis.

5. **Conclusion:**
- The most stable carbanion is **Option A (CH3CH2-)** because it has the least inductive effect from alkyl groups, resulting in a more stable negative charge.

### Final Answer:
**The most stable carbanion among the following is Option A (CH3CH2-).**

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