Explain which is a stronger acid.
`CH_(3)- overset(O)overset(||)C - CH_(3) " & " CH_(3)- overset(O)overset(||)C - CH_(2)CN `

Answer

To determine which of the two compounds is a stronger acid, we need to analyze their ability to lose a proton (H⁺) and the stability of the resulting carbanion.

### Step 1: Identify the Compounds
The two compounds we are comparing are:
1. **Compound A:** CH₃C(=O)CH₃ (Acetone)
2. **Compound B:** CH₃C(=O)CH₂CN (Acetyl cyanide)

### Step 2: Determine the Acidic Hydrogen
In both compounds, the acidic hydrogen is the one attached to the carbon adjacent to the carbonyl group (C=O).

- For **Compound A**, the acidic hydrogen is from the CH₃ group adjacent to the carbonyl.
- For **Compound B**, the acidic hydrogen is from the CH₂ group adjacent to the carbonyl.

### Step 3: Remove the Acidic Hydrogen
When we remove the acidic hydrogen (H⁺) from each compound, we form the corresponding carbanions:

- **From Compound A:**
- CH₃C(=O)CH₃ → CH₃C(=O)C⁻H₂ (carbanion)

- **From Compound B:**
- CH₃C(=O)CH₂CN → CH₃C(=O)C⁻H + CN (carbanion)

### Step 4: Analyze the Stability of the Carbanions
The stability of the carbanion is crucial in determining the strength of the acid. A more stable carbanion indicates a stronger acid.

- **For Compound A's Carbanion:**
- The carbanion is stabilized by resonance with the carbonyl group. However, both methyl groups (CH₃) do not provide significant stabilization.

- **For Compound B's Carbanion:**
- The carbanion is also stabilized by resonance with the carbonyl group. Additionally, the presence of the cyano group (CN) is an electron-withdrawing group. This group pulls electron density away from the carbanion, further stabilizing the negative charge.

### Step 5: Compare the Stability
- The carbanion from **Compound B** is more stable due to the dual stabilization:
1. Resonance stabilization from the carbonyl group.
2. Electron-withdrawing effect from the cyano group.

### Conclusion
Since the carbanion formed from **Compound B (CH₃C(=O)CH₂CN)** is more stable than that from **Compound A (CH₃C(=O)CH₃)**, **Compound B is the stronger acid**.

### Summary
- **Stronger Acid:** CH₃C(=O)CH₂CN (Acetyl cyanide)
- **Weaker Acid:** CH₃C(=O)CH₃ (Acetone)