Phenol can be tested by

Options

A. Libermann nitroso test
B. Neutral `FeCl_3` solution
C. Bromine water
D. all of the above

Answer

To determine how phenol can be tested, we will analyze the various reagents mentioned in the question and their interactions with phenol.

### Step-by-Step Solution:

1. **Understanding Phenol**:
- Phenol is an aromatic compound with a hydroxyl (-OH) group attached to a benzene ring. It has distinct chemical properties that can be tested using various reagents.

2. **Testing with FeCl3 Solution**:
- When phenol is treated with ferric chloride (FeCl3) solution, it forms a colored complex. The reaction typically results in a purple or violet color, indicating the presence of phenol.

3. **Testing with Bromine Water**:
- Phenol can also react with bromine water. When bromine water is added to phenol, it decolorizes the bromine and forms a white precipitate of 2,4,6-tribromophenol. This reaction indicates the presence of phenolic compounds.

4. **Liebermann's Test**:
- The Liebermann test (also known as the Liebermann-Burchard test) involves the reaction of phenol with sodium nitrite (NaNO2) and concentrated sulfuric acid (H2SO4). This test produces a deep blue or green color, which changes to red upon dilution with water, confirming the presence of phenol.

5. **Conclusion**:
- Since phenol can be tested by all the mentioned reagents (FeCl3 solution, Bromine water, and through the Liebermann test), the correct answer is that phenol can be tested by all of the above.

### Final Answer:
- **Option D: All of the above**