Which of the following does not given iodoform test :

Options

A. 2-pentanone
B. ethanol
C. ethanal
D. 3-pentanone

Explanation

To determine which of the following compounds does not give the iodoform test, we need to identify the presence of the specific functional group that reacts to give a positive result. The functional group responsible for the iodoform reaction is the methyl ketone group (CH3C=O) or any compound that can be oxidized to form this group.

### Step-by-Step Solution:

1. **Identify the Functional Group**: The iodoform test is positive for compounds that contain the methyl ketone group (CH3C=O) or alcohols that can be oxidized to form this group.

2. **Analyze Each Option**:
- **Option 1: Pentan-2-one (CH3C(=O)C4H9)**: This compound contains the methyl ketone group (CH3C=O), hence it will give a positive iodoform test.
- **Option 2: Ethanol (CH3CH2OH)**: Ethanol can be oxidized to acetaldehyde (CH3C=O), which contains the methyl ketone group, so it will also give a positive iodoform test.
- **Option 3: Ethyl alcohol (CH3CH2OH)**: Similar to ethanol, it can be oxidized to acetaldehyde, which contains the methyl ketone group, thus giving a positive iodoform test.
- **Option 4: Pentan-3-one (C5H10O)**: This compound does not contain the methyl ketone group (CH3C=O). The ketone group is located at the second carbon, which does not satisfy the criteria for the iodoform test.

3. **Conclusion**: Based on the analysis, Pentan-3-one does not give the iodoform test because it lacks the necessary methyl ketone structure.

### Final Answer:
**Pentan-3-one does not give the iodoform test.**