Which of the following compound undergoes haloform reaction?

Options

A. `CH_3 COCH_3`
B. `HCHO`
C. `CH_3CH_2Br`
D. `CH_3 -O-CH_3`

Explanation

To determine which compound undergoes the haloform reaction, we need to understand the requirements for a compound to participate in this reaction. The haloform reaction typically occurs with compounds that have the following characteristics:

1. **Presence of a methyl ketone or a compound that can be oxidized to a methyl ketone**: The compound must have a methyl group adjacent to the carbonyl group (C=O).
2. **Alpha hydrogens**: The compound must have at least one alpha hydrogen (hydrogens attached to the carbon adjacent to the carbonyl carbon).

### Step-by-Step Solution:

1. **Identify the Compounds**: List the compounds provided in the question. For example, let's say the options are:
- A: CH3COCH3 (Acetone)
- B: CH3CH2COOH (Propanoic acid)
- C: CH3CHO (Acetaldehyde)
- D: C6H5COCH3 (Acetophenone)

2. **Check for Methyl Ketone Structure**:
- **Option A (Acetone)**: This is a methyl ketone (CH3COCH3) and has two alpha hydrogens. It can undergo the haloform reaction.
- **Option B (Propanoic acid)**: This is a carboxylic acid and does not have a methyl ketone structure. It cannot undergo the haloform reaction.
- **Option C (Acetaldehyde)**: This is an aldehyde and does not have a methyl ketone structure. It cannot undergo the haloform reaction.
- **Option D (Acetophenone)**: This is a ketone but does not have a methyl group adjacent to the carbonyl. It cannot undergo the haloform reaction.

3. **Conclusion**: The only compound that meets the criteria for the haloform reaction is **Option A: CH3COCH3 (Acetone)**.

### Final Answer:
The compound that undergoes the haloform reaction is **Acetone (CH3COCH3)**.