Phenol can be distinguished from ethanol by the following reagents except

Options

A. Sodium
B. Neutral `FeCl_(3)`
C. Phthalic anhydride/conc. `H_(2)SO_(4) and NaOH`
D. `Br_(2)//H_(2)O`

Answer

To solve the question of how phenol can be distinguished from ethanol by various reagents, we will analyze each reagent mentioned and determine which one does not differentiate between the two compounds.

### Step-by-Step Solution:

1. **Identify the Structures**:
- **Phenol**: The chemical formula is C6H5OH, which consists of a benzene ring with a hydroxyl (–OH) group attached.
- **Ethanol**: The chemical formula is C2H5OH, which is a simple alcohol with a two-carbon chain and a hydroxyl (–OH) group.

2. **Reagent: Sodium (Na)**:
- When phenol reacts with sodium, it produces sodium phenoxide and hydrogen gas:
\[ \text{C6H5OH} + \text{Na} \rightarrow \text{C6H5O}^- \text{Na}^+ + \text{H}_2(g) \]
- When ethanol reacts with sodium, it produces sodium ethoxide and hydrogen gas:
\[ \text{C2H5OH} + \text{Na} \rightarrow \text{C2H5O}^- \text{Na}^+ + \text{H}_2(g) \]
- **Conclusion**: Both phenol and ethanol react with sodium to produce hydrogen gas, so this reagent cannot distinguish between them.

3. **Reagent: Iron(III) Chloride (FeCl3)**:
- Phenol reacts with FeCl3 to form a violet-colored complex:
\[ \text{C6H5OH} + \text{FeCl3} \rightarrow \text{Complex (violet)} + \text{HCl} \]
- Ethanol does not form this complex.
- **Conclusion**: This reagent can distinguish between phenol and ethanol.

4. **Reagent: Phthalic Anhydride in Concentrated H2SO4**:
- Phenol reacts with phthalic anhydride to form a product that can be identified in acid-base titrations.
- Ethanol does not react in the same way.
- **Conclusion**: This reagent can distinguish between phenol and ethanol.

5. **Reagent: Bromine Water**:
- Phenol reacts with bromine water to form 2,4,6-tribromophenol, which precipitates out:
\[ \text{C6H5OH} + 3\text{Br2} \rightarrow \text{C6H2Br3OH} + 3\text{HBr} \]
- Ethanol does not react with bromine water in the same manner.
- **Conclusion**: This reagent can distinguish between phenol and ethanol.

### Final Answer:
The reagent that cannot distinguish between phenol and ethanol is **Sodium (Na)**.