Which of the following will not form a yellow precipitate on heating with an alkaline solution of iodine?

Options

A. `CH_3CH_2CH(OH)CH_3`
B. `CH_3OH`
C. `CH_3CH_2OH`
D. `CH_3CH(OH)CH_3`

Answer

To solve the question of which compound will not form a yellow precipitate when heated with an alkaline solution of iodine, we need to understand the Iodoform test.

### Step-by-Step Solution:

1. **Understand the Iodoform Test**:
- The Iodoform test is a qualitative test used to identify the presence of certain types of compounds, particularly those that contain a methyl ketone (R-CO-CH3) or a secondary alcohol that can be oxidized to a methyl ketone.
- The formation of a yellow precipitate indicates a positive result for the presence of these functional groups.

2. **Identify the Requirement for the Test**:
- For a compound to give a positive Iodoform test, it must have a methyl group adjacent to a carbonyl group (C=O) or a hydroxyl group (OH) that can be oxidized to a carbonyl.
- This means that the compound must have a beta hydrogen (hydrogen atom on the carbon adjacent to the carbonyl or hydroxyl carbon).

3. **Analyze the Given Options**:
- We need to analyze each option to determine whether it contains a beta hydrogen or not.
- If a compound lacks a beta hydrogen, it will not give a yellow precipitate upon treatment with an alkaline iodine solution.

4. **Conclusion**:
- After analyzing the options, we find that one of the compounds does not have a beta hydrogen. This compound will not form a yellow precipitate when heated with an alkaline solution of iodine.

5. **Final Answer**:
- Therefore, the correct answer is the compound that does not have a beta hydrogen.