`PhCOOH, PhCH_3` can be separated by

Options

A. `KMnO_4`
B. aq. `NaHCO_3` + n-hexane
C. `H_2O`
D. None of these

Explanation

To separate benzoic acid (PhCOOH) and toluene (PhCH₃), we can utilize their differing solubilities in certain solvents. Here’s a step-by-step solution:

### Step 1: Identify the compounds
- **Benzoic acid (PhCOOH)**: This is an organic acid that is soluble in water and basic solutions.
- **Toluene (PhCH₃)**: This is an aromatic hydrocarbon that is non-polar and soluble in non-polar solvents like n-hexane.

### Step 2: Choose a suitable solvent
- **Sodium bicarbonate (NaHCO₃)**: This is a basic solution that can react with benzoic acid to form sodium benzoate (PhCOONa), which is soluble in water.
- **n-Hexane**: This is a non-polar solvent that will dissolve toluene but not benzoic acid.

### Step 3: Perform the separation
1. **Add sodium bicarbonate to the mixture**: When sodium bicarbonate is added to the mixture of benzoic acid and toluene, the benzoic acid will react to form sodium benzoate, which is soluble in the aqueous layer.
- Reaction:
\[ \text{PhCOOH} + \text{NaHCO}_3 \rightarrow \text{PhCOONa} + \text{H}_2\text{O} + \text{CO}_2 \]
2. **Extract the aqueous layer**: The sodium benzoate will remain in the aqueous layer, while toluene will remain in the organic layer (n-hexane).
3. **Separate the layers**: Use a separating funnel to separate the aqueous layer (containing sodium benzoate) from the organic layer (containing toluene).

### Conclusion
The correct method to separate benzoic acid and toluene is by using sodium bicarbonate to convert benzoic acid into a soluble salt, while toluene remains in the organic phase.

### Final Answer
**Benzoic acid (PhCOOH) and toluene (PhCH₃) can be separated by using sodium bicarbonate and n-hexane.**

---