Explain which is a stronger acid.
`CH_(3) - CHO " "CH_(3) - NO_(2)`

Answer

To determine which compound is a stronger acid between CH₃CHO (acetaldehyde) and CH₃NO₂ (nitromethane), we can analyze the effects of their functional groups on acidity.

### Step-by-Step Solution:

1. **Identify the Compounds**:
- The first compound is CH₃CHO (acetaldehyde), which contains an aldehyde functional group (-CHO).
- The second compound is CH₃NO₂ (nitromethane), which contains a nitro functional group (-NO₂).

2. **Understand Acidity**:
- Acidity is related to the ability of a compound to donate a proton (H⁺). The more stable the conjugate base formed after deprotonation, the stronger the acid.

3. **Analyze the Functional Groups**:
- The aldehyde group (-CHO) is a weak electron-withdrawing group due to its carbonyl (C=O) structure.
- The nitro group (-NO₂) is a strong electron-withdrawing group due to its resonance and inductive effects.

4. **Stability of Conjugate Bases**:
- When CH₃CHO donates a proton, it forms CH₃C(O⁻)H, where the negative charge is partially stabilized by the carbonyl group.
- When CH₃NO₂ donates a proton, it forms CH₃NO₂⁻, where the negative charge is highly stabilized by the strong electron-withdrawing nitro group.

5. **Comparison of Stability**:
- The conjugate base of CH₃NO₂ (nitromethane) is more stable than that of CH₃CHO (acetaldehyde) because the nitro group can delocalize the negative charge effectively through resonance and inductive effects.

6. **Conclusion**:
- Since the conjugate base of CH₃NO₂ is more stable than that of CH₃CHO, CH₃NO₂ is the stronger acid.

### Final Answer:
**CH₃NO₂ (nitromethane) is a stronger acid than CH₃CHO (acetaldehyde).**