Which of the following compound will give a yellow precipitate with iodine and alkali?

Options

A. a.2-Hydroxy
B. b.Acetophenone
C. c.Methyl acetone
D. d.Acetone

Explanation

To determine which of the given compounds will give a yellow precipitate with iodine and alkali, we need to identify compounds that can undergo the iodoform reaction. The iodoform reaction is characteristic of compounds that have a methyl ketone group (RCOCH3) or a secondary alcohol with a methyl group adjacent to the hydroxyl group (RCHOHCH3).

### Step-by-Step Solution:

1. **Identify the Functional Groups**:
- We need to look for compounds that have either a methyl ketone structure (RCOCH3) or a secondary alcohol with a methyl group (RCHOHCH3).

2. **Analyze Each Compound**:
- **Option A**: Check if it has the functional unit RCOCH3 or RCHOHCH3.
- **Option B**: Check for the same functional units.
- **Option C**: Check if it has the required functional groups.
- **Option D**: Check for the presence of the functional groups.

3. **Determine Which Compounds React**:
- If a compound contains the functional group RCOCH3 (methyl ketone) or RCHOHCH3 (secondary alcohol), it will react with iodine and alkali to produce a yellow precipitate of iodoform (CHI3).

4. **Conclusion**:
- After analyzing the options:
- **Option A**: Contains the functional group, thus gives a yellow precipitate.
- **Option B**: Contains the functional group, thus gives a yellow precipitate.
- **Option C**: Does not contain the functional group, thus does not give a yellow precipitate.
- **Option D**: Contains the functional group, thus gives a yellow precipitate.

5. **Final Answer**: The compounds that will give a yellow precipitate with iodine and alkali are **Option A, Option B, and Option D**.