A mixture of phenol and aromatic carboxylic acid can be separated easily by using a solution of :

Options

A. NaOH
B. lime
C. `NaHCO_3`
D. `HNO_3`

Explanation

To solve the problem of separating a mixture of phenol and aromatic carboxylic acid, we need to consider their chemical properties and how they react with different reagents.

### Step-by-Step Solution:

1. **Identify the Compounds**:
- Phenol has the structure: C6H5OH (a benzene ring with a hydroxyl group).
- Aromatic carboxylic acid has the structure: C6H5COOH (a benzene ring with a carboxyl group).

2. **Consider the Reactivity with Sodium Bicarbonate (NaHCO3)**:
- Phenol is a weak acid and does not react with sodium bicarbonate, which is also a weak base. Therefore, no reaction occurs between phenol and NaHCO3.
- Aromatic carboxylic acids, on the other hand, are stronger acids and will react with sodium bicarbonate to form sodium salt, carbon dioxide (CO2), and water.

3. **Write the Reaction for Aromatic Carboxylic Acid**:
- The reaction can be represented as:
\[ \text{C6H5COOH} + \text{NaHCO3} \rightarrow \text{C6H5COONa} + \text{CO2} + \text{H2O} \]
- The formation of carbon dioxide gas (CO2) can be observed as bubbling or effervescence.

4. **Separation of the Components**:
- Since phenol does not react with NaHCO3, it remains in the solution, while the aromatic carboxylic acid reacts and forms a soluble sodium salt.
- By adding NaHCO3 to the mixture, we can separate phenol from the aromatic carboxylic acid because the carboxylic acid will convert into its sodium salt, which is soluble in water, while phenol will remain unreacted.

5. **Conclusion**:
- Therefore, the correct solution to separate phenol from aromatic carboxylic acid is to use a solution of sodium bicarbonate (NaHCO3).

### Final Answer:
The mixture of phenol and aromatic carboxylic acid can be separated easily by using a solution of **NaHCO3**.