Phenol and benzoic acid is distinguished by

Options

A. NaOH
B. `NaHCO_(3)`
C. `Na_(2)CO_(3)`
D. `H_(2)SO_(4)`

Answer

To distinguish between phenol and benzoic acid, we can follow these steps:

### Step 1: Understand the Acidity of Phenol and Benzoic Acid
- **Phenol** is a weak acid, while **benzoic acid** is a stronger acid. This difference in acidity is crucial for distinguishing between the two compounds.

### Step 2: Use Sodium Bicarbonate (NaHCO3) for the Reaction
- Sodium bicarbonate is a mild base that reacts with stronger acids to produce carbon dioxide (CO2) gas.

### Step 3: Perform the Reaction
- When sodium bicarbonate is added to benzoic acid, it reacts to form carbonic acid (H2CO3), which then decomposes into water (H2O) and carbon dioxide (CO2) gas:
\[ \text{Benzoic Acid} + \text{NaHCO}_3 \rightarrow \text{NaBenzoate} + \text{H}_2\text{CO}_3 \rightarrow \text{NaBenzoate} + \text{H}_2\text{O} + \text{CO}_2 \uparrow \]
- In contrast, when sodium bicarbonate is added to phenol, there is no reaction because phenol is not acidic enough to react with NaHCO3.

### Step 4: Observe the Results
- If you observe the evolution of gas (bubbles of CO2), it indicates the presence of benzoic acid. If there is no gas evolution, it indicates the presence of phenol.

### Conclusion
- By using sodium bicarbonate, we can effectively distinguish between phenol and benzoic acid based on their reactivity with the bicarbonate.