Iodoform test is not given by:

Options

A. 2–pentanone
B. 3–pentanone
C. Ethanol
D. None of these

Answer

To determine which compound does not give the Iodoform test, we need to understand the criteria for a compound to be positive for this test. The Iodoform test is primarily used to identify methyl ketones and some alcohols that can be oxidized to form methyl ketones.

### Step-by-Step Solution:

1. **Understand the Iodoform Test**:
- The Iodoform test is a qualitative test used to identify the presence of methyl ketones (R-CO-CH3) or compounds that can be oxidized to form such structures.
- The reaction involves the treatment of the compound with iodine (I2) and sodium hydroxide (NaOH), resulting in the formation of iodoform (CHI3), which is a yellow precipitate.

2. **Identify the Structure Required for a Positive Test**:
- For a compound to give a positive Iodoform test, it must have a methyl ketone structure (C=O adjacent to a CH3 group) or be an alcohol that can be oxidized to such a structure.

3. **Analyze the Given Options**:
- **Option 1: 2-Pentanone**:
- Structure: CH3-CO-CH2-CH2-CH3.
- This compound has a methyl ketone structure (C=O next to CH3), so it will give a positive Iodoform test.
- **Option 2: 3-Pentanone**:
- Structure: CH3-CH2-CO-CH2-CH3.
- This compound does not have a methyl ketone structure (C=O is not adjacent to CH3), so it will not give a positive Iodoform test.
- **Option 3: Ethanol**:
- Structure: CH3-CH2-OH.
- Ethanol can be oxidized to acetaldehyde (CH3CHO), which has a methyl ketone structure, thus it will give a positive Iodoform test.
- **Option 4: None of these**:
- This option is irrelevant since we have already identified a compound that does not give the Iodoform test.

4. **Conclusion**:
- Based on the analysis, the compound that does not give the Iodoform test is **3-Pentanone**.

### Final Answer:
**3-Pentanone does not give the Iodoform test.**