Which of the following alcohol will show positive iodoform test ?

Options

A. methanol
B. Propan 2-ol
C. pentan 3-ol
D. None of these

Explanation

To determine which alcohol will show a positive iodoform test, we need to understand the conditions required for this test. The iodoform test is positive for alcohols that can be oxidized to form a methyl ketone (a ketone with a methyl group adjacent to the carbonyl group).

### Step-by-Step Solution:

1. **Identify the Alcohols**: We need to examine the given alcohols to see if they can be oxidized to form a methyl ketone. The alcohols mentioned are methanol, propane-2-ol, and pentane-3-ol.

2. **Check Methanol**:
- Structure: Methanol (CH₃OH).
- Analysis: Methanol is a primary alcohol and cannot be oxidized to a ketone. Therefore, it cannot show a positive iodoform test.

3. **Check Propan-2-ol**:
- Structure: Propan-2-ol (CH₃CHOHCH₃).
- Analysis: When oxidized, propan-2-ol forms acetone (CH₃COCH₃), which is a methyl ketone. Since it has a methyl group adjacent to the carbonyl group, it will show a positive iodoform test.

4. **Check Pentane-3-ol**:
- Structure: Pentane-3-ol (CH₃CH₂CHOHCH₂CH₃).
- Analysis: Upon oxidation, pentane-3-ol forms a ketone (CH₃CH₂C(=O)CH₂CH₃). This ketone does not have a methyl group adjacent to the carbonyl group, so it will not show a positive iodoform test.

5. **Conclusion**:
- Methanol: Negative iodoform test.
- Propan-2-ol: Positive iodoform test.
- Pentane-3-ol: Negative iodoform test.

Thus, the only alcohol that shows a positive iodoform test is **propan-2-ol**.

### Final Answer:
**Propan-2-ol (Option 2) will show a positive iodoform test.**

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