Which of the following compound does not give iodoform test ?

Options

A. Penta-3-one
B. Penta-2-one
C. Propanone
D. Ethanol

Explanation

To determine which of the following compounds does not give the iodoform test, we need to understand the conditions under which the iodoform test is positive. The iodoform test is typically given by:

1. **Methyl ketones** (compounds with the structure RCOCH3, where R can be any alkyl group).
2. **Ethanol** and other primary alcohols that can be oxidized to methyl ketones.
3. **Secondary alcohols** that can be oxidized to methyl ketones.

The key factor for a compound to give a positive iodoform test is the presence of an **alpha methyl group** (a methyl group adjacent to the carbonyl carbon).

### Step-by-Step Solution:

1. **Identify the Compounds**: List the compounds provided in the question. For this example, let’s assume the compounds are:
- Ethanol (C2H5OH)
- Propan-2-one (acetone, C3H6O)
- Pent-2-one (C5H10O)
- Pent-3-one (C5H10O)

2. **Analyze Each Compound**:
- **Ethanol (C2H5OH)**: This is a primary alcohol and can be oxidized to acetaldehyde (which has an alpha methyl group). Therefore, it gives a positive iodoform test.
- **Propan-2-one (C3H6O)**: This is a methyl ketone (CH3COCH3) and has an alpha methyl group. It gives a positive iodoform test.
- **Pent-2-one (C5H10O)**: This is also a methyl ketone (CH3C(=O)C4H9) with an alpha methyl group. It gives a positive iodoform test.
- **Pent-3-one (C5H10O)**: This compound has the structure CH3C(=O)C2H5C2H5. It does not have an alpha methyl group adjacent to the carbonyl carbon, so it does not give a positive iodoform test.

3. **Conclusion**: The compound that does not give the iodoform test is **Pent-3-one**.

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