Which of the following does not undergo Hell-Volhard-Zelinsky reaction ?

Options

A. HCOOH
B. `C CI_(3)COOH`
C. `C_(6)H_(5)COOH`
D. All of these

Answer

To determine which of the given compounds does not undergo the Hell-Volhard-Zelinsky (HVZ) reaction, we need to understand the requirements for this reaction to occur. The HVZ reaction typically involves the halogenation of carboxylic acids at the alpha carbon, which must have alpha hydrogens.

### Step-by-Step Solution:

1. **Identify the Requirement for HVZ Reaction**:
- The compound must have a carboxylic acid functional group (-COOH).
- There must be at least one alpha hydrogen present on the carbon adjacent to the carbonyl group (the carbon of the -COOH group).

2. **Analyze Each Option**:
- **Option 1: H-C(O)OH (Formic Acid)**:
- This compound has a carbonyl group (C=O) and an adjacent carbon (the carbon attached to the -COOH). However, there are no hydrogens on this adjacent carbon, so it does not have alpha hydrogens.
- **Option 2: CCl3COOH (Trichloroacetic Acid)**:
- This compound has a carbonyl group and an adjacent carbon (CCl3). The adjacent carbon (CCl3) does not have any hydrogen atoms, so it also lacks alpha hydrogens.
- **Option 3: C6H5COOH (Benzoic Acid)**:
- This compound has a carbonyl group and an adjacent carbon (the carbon of the benzene ring). The adjacent carbon does not have any hydrogen atoms, so it does not have alpha hydrogens.
- **Option 4: COOH (Carboxylic Acid)**:
- This is a general reference to carboxylic acids, but without a specific structure, we can assume it refers to a simple carboxylic acid. If it does not have an adjacent carbon with alpha hydrogens, it will not undergo the HVZ reaction.

3. **Conclusion**:
- Since all the options provided (Formic Acid, Trichloroacetic Acid, Benzoic Acid) lack alpha hydrogens, none of these compounds can undergo the HVZ reaction.

Thus, the answer to the question "Which of the following does not undergo Hell-Volhard-Zelinsky reaction?" is **all of these**.