Which of the following reagents is used to separate benzoic acid from phenol?

Options

A. Dil. HCl
B. Dil.`H_(2)SO_(4)`
C. 5% aq. NaOH
D. 5% aq. `NaHCO_(3)`

Explanation

To separate benzoic acid from phenol, we can utilize a reagent that selectively reacts with benzoic acid to form a soluble compound, while leaving phenol unaffected. The reagent used for this separation is 5% aqueous sodium bicarbonate (NaHCO3).

### Step-by-Step Solution:

1. **Identify the Compounds**:
- We have two compounds: benzoic acid (C6H5COOH) and phenol (C6H5OH).

2. **Understand the Properties**:
- Benzoic acid is a weak acid and can react with bases to form soluble salts.
- Phenol is a weak acid as well but does not react with sodium bicarbonate.

3. **Choose the Reagent**:
- The reagent chosen for this separation is 5% aqueous sodium bicarbonate (NaHCO3).

4. **Reaction of Benzoic Acid with Sodium Bicarbonate**:
- When benzoic acid is treated with sodium bicarbonate, it reacts to form sodium benzoate, which is soluble in water:
\[ C6H5COOH + NaHCO3 \rightarrow C6H5COONa + H2O + CO2 \]
- This reaction produces sodium benzoate (C6H5COONa), which is soluble in the aqueous layer.

5. **Behavior of Phenol**:
- Phenol does not react with sodium bicarbonate and remains as a separate oily layer.

6. **Separation of Layers**:
- After the reaction, we will have two distinct layers: the aqueous layer containing sodium benzoate and the organic layer containing phenol.

7. **Conclusion**:
- The two compounds can now be easily separated by decantation or using a separating funnel.

### Final Answer:
The reagent used to separate benzoic acid from phenol is **5% aqueous sodium bicarbonate (NaHCO3)**.