A compound that gives positive iodoform test is

Options

A. 1-pentanol
B. 2-pentanone
C. 3-pentanone
D. pentanal

Answer

To determine which compound gives a positive iodoform test, we need to identify compounds that contain the specific structural unit that can lead to this reaction. The iodoform test is positive for compounds that have the structure RCOCH3 (where R can be any alkyl group) or for secondary alcohols that can be oxidized to such ketones.

### Step-by-Step Solution:

1. **Understanding the Iodoform Test**:
- The iodoform test is used to identify the presence of a methyl ketone (RCOCH3) or a secondary alcohol that can be oxidized to a methyl ketone.

2. **Analyzing the Options**:
- We will analyze each of the given compounds to see if they can give a positive iodoform test.

3. **Option 1: 1-Pentanol (C5H12O)**:
- Structure: CH3-CH2-CH2-CH2-CH2-OH
- Upon oxidation, 1-pentanol will convert to pentanal (an aldehyde), which does not have the required methyl ketone structure (RCOCH3).
- **Conclusion**: 1-pentanol does not give a positive iodoform test.

4. **Option 2: 2-Pentanone (C5H10O)**:
- Structure: CH3-CO-CH2-CH2-CH3
- This compound contains the structure RCOCH3 (where R is the ethyl group, CH2-CH3).
- Therefore, 2-pentanone can give a positive iodoform test.
- **Conclusion**: 2-pentanone gives a positive iodoform test.

5. **Option 3: 3-Pentanone (C5H10O)**:
- Structure: CH3-CH2-CO-CH2-CH3
- This compound does not have the methyl group directly attached to the carbonyl carbon (C=O).
- **Conclusion**: 3-pentanone does not give a positive iodoform test.

6. **Option 4: Pentanal (C5H10O)**:
- Structure: CH3-CH2-CH2-CH2-CHO
- This is an aldehyde and does not have the methyl ketone structure.
- **Conclusion**: Pentanal does not give a positive iodoform test.

### Final Answer:
The compound that gives a positive iodoform test is **2-Pentanone**.

---