Which of the following orders correctly depicts the decreasing order of stability of carbanion?

Options

A.
B. `OHC-underset(CHO)underset(|)overline(C)-CHO gt OHC- overline(C)H-CHO gt H_(3)C- underset(O)underset(||)(C)-overline(C)H-underset(O)underset(||)(C)-CH_(3) gt overline(C)H_(3)-CHO`
C. `overline(C)H_(2)NO_(2) lt overline(C)H_(2)CN lt overline(C)H_(2)Cl lt overline(C)H_(2)CH_(3)`
D.

Answer

To determine the decreasing order of stability of carbanions, we need to consider the effect of substituents on the carbanion. The stability of carbanions is influenced by the presence of electron-withdrawing groups (EWGs) and electron-donating groups (EDGs).

### Step-by-Step Solution:

1. **Understanding Carbanion Stability**:
- Carbanions are negatively charged carbon species. Their stability is primarily influenced by the nature of substituents attached to the carbon atom bearing the negative charge.
- Electron-withdrawing groups stabilize carbanions by delocalizing the negative charge, while electron-donating groups destabilize them by increasing electron density.

2. **Identifying Electron-Withdrawing and Electron-Donating Groups**:
- Common electron-withdrawing groups include: -NO2 (nitro), -CN (cyano), -CHO (aldehyde), and -CO (ketone).
- Common electron-donating groups include: -CH3 (methyl), -OCH3 (methoxy), and other alkyl groups.

3. **Analyzing the Given Options**:
- **Option 1**: Contains electron-donating groups, which would destabilize the carbanion.
- **Option 2**: Contains multiple -CHO groups, which are strong electron-withdrawing groups. This option is likely to be the most stable.
- **Option 3**: Contains a mix of electron-donating (CH3) and electron-withdrawing groups (Cl, CN, NO2), but the presence of CH3 destabilizes it.
- **Option 4**: Contains an electron-donating group (OCH3) which destabilizes the carbanion, making it incorrect.

4. **Conclusion**:
- After analyzing the effects of the substituents in each option, **Option 2** is the correct answer as it has the highest number of electron-withdrawing groups, thus stabilizing the carbanion the most.

### Final Answer:
The correct order depicting the decreasing order of stability of carbanions is given by **Option 2**.