Which of the following acids will give maximum yield of alkyl chloride in Huns diecker reaction

Options

A. `CH_3CH_2CH_2COOH`
B. `(CH_3)_2CHCOOH`
C. `(CH_3)_3CCOOH`
D. `C_6H_5CH(CH_3)COOH`

Answer

To determine which acid will give the maximum yield of alkyl chloride in the Hunsdiecker reaction, we need to analyze the stability of the radicals formed from the different carboxylic acids involved in the reaction. Here’s a step-by-step solution:

### Step 1: Understand the Hunsdiecker Reaction
The Hunsdiecker reaction involves the conversion of silver salts of carboxylic acids into alkyl halides (either bromides or chlorides) using halogens (Br2 or Cl2) in a solvent like carbon tetrachloride (CCl4). The general reaction can be represented as follows:

\[ RCOOAg + Br_2 \rightarrow RBr + CO_2 + AgBr \]

### Step 2: Identify the Carboxylic Acids
Assuming we have four carboxylic acids (A, B, C, D), we need to evaluate the radicals formed from each acid. The acids will have different alkyl groups attached, which will influence the stability of the resulting radicals.

### Step 3: Determine the Radicals
For each carboxylic acid, we will derive the corresponding alkyl radical:

- **For Acid A:** The radical formed will be \( R_A \cdot \) (e.g., \( CH_3CH_2CH_2 \cdot \))
- **For Acid B:** The radical formed will be \( R_B \cdot \) (e.g., \( CH_3CH \cdot \))
- **For Acid C:** The radical formed will be \( R_C \cdot \) (e.g., \( (CH_3)_2C \cdot \))
- **For Acid D:** The radical formed will be \( R_D \cdot \) (e.g., \( C_6H_5CH_2 \cdot \))

### Step 4: Analyze Radical Stability
The stability of the radicals can be judged based on:
1. **Resonance:** Radicals that can delocalize their unpaired electron through resonance are more stable.
2. **Hyperconjugation:** Radicals that have more adjacent alkyl groups can stabilize the radical through hyperconjugation.
3. **Inductive Effect:** Electron-donating groups can stabilize radicals.

- **Radical A:** Stabilized by hyperconjugation (2 alpha hydrogens).
- **Radical B:** Stabilized by hyperconjugation (3 alpha hydrogens).
- **Radical C:** Stabilized by hyperconjugation (9 alpha hydrogens).
- **Radical D:** Stabilized by resonance (due to the benzene ring) and hyperconjugation (3 alpha hydrogens).

### Step 5: Conclusion
Among the radicals formed, the radical from Acid D (which has resonance stabilization due to the benzene ring) is the most stable. Therefore, the Hunsdiecker reaction will proceed most readily with Acid D, resulting in the maximum yield of alkyl chloride.

### Final Answer
The acid that will give the maximum yield of alkyl chloride in the Hunsdiecker reaction is **Acid D**.

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