Benzoic acid and carbolic acid can be distiguished by:

Options

A. a.Aqueous `NaHCO_(3)`
B. b.Netural `FeCl_(3)`
C. c.Aqueous `NaOH`
D. d.Aqueous `NH_(3)`

Explanation

To distinguish between benzoic acid and carbolic acid (phenol), we can analyze their reactions with various reagents. Here’s a step-by-step solution:

### Step 1: Identify the Compounds
- **Benzoic Acid**: It is a carboxylic acid with the formula C6H5COOH.
- **Carbolic Acid (Phenol)**: It is an aromatic compound with the formula C6H5OH.

### Step 2: Analyze the Reagents
We have four reagents to consider:
1. Aqueous NaHCO3 (Sodium Bicarbonate)
2. Neutral FeCl3 (Ferric Chloride)
3. Aqueous NaOH (Sodium Hydroxide)
4. Aqueous Ammonia

### Step 3: Reaction with Aqueous NaHCO3
- **Benzoic Acid**: Reacts with NaHCO3 to produce carbon dioxide (CO2), resulting in brisk effervescence.
\[ \text{C}_6\text{H}_5\text{COOH} + \text{NaHCO}_3 \rightarrow \text{C}_6\text{H}_5\text{COONa} + \text{CO}_2 + \text{H}_2\text{O} \]
- **Phenol**: Does not react with NaHCO3, so no effervescence is observed.

**Conclusion**: Aqueous NaHCO3 can distinguish between benzoic acid and phenol.

### Step 4: Reaction with Neutral FeCl3
- **Benzoic Acid**: Forms a buff-colored precipitate (ferric benzoate).
\[ \text{C}_6\text{H}_5\text{COOH} + \text{FeCl}_3 \rightarrow \text{C}_6\text{H}_5\text{COOFe} + 3\text{HCl} \]
- **Phenol**: Forms a violet-colored complex (ferric phenoxide).
\[ \text{C}_6\text{H}_5\text{OH} + \text{FeCl}_3 \rightarrow \text{C}_6\text{H}_5\text{OFe} + 3\text{HCl} \]

**Conclusion**: Neutral FeCl3 can also distinguish between benzoic acid and phenol.

### Step 5: Reaction with Aqueous NaOH
- **Benzoic Acid**: Reacts with NaOH to form sodium benzoate and water.
\[ \text{C}_6\text{H}_5\text{COOH} + \text{NaOH} \rightarrow \text{C}_6\text{H}_5\text{COONa} + \text{H}_2\text{O} \]
- **Phenol**: Also reacts with NaOH to form sodium phenoxide and water.
\[ \text{C}_6\text{H}_5\text{OH} + \text{NaOH} \rightarrow \text{C}_6\text{H}_5\text{ONa} + \text{H}_2\text{O} \]

**Conclusion**: Aqueous NaOH cannot distinguish between benzoic acid and phenol as both react similarly.

### Step 6: Reaction with Aqueous Ammonia
- **Benzoic Acid**: Reacts with ammonia to form benzamide and water.
\[ \text{C}_6\text{H}_5\text{COOH} + \text{NH}_3 \rightarrow \text{C}_6\text{H}_5\text{C(O)NH}_2 + \text{H}_2\text{O} \]
- **Phenol**: Reacts with ammonia to form aniline and water.
\[ \text{C}_6\text{H}_5\text{OH} + \text{NH}_3 \rightarrow \text{C}_6\text{H}_5\text{NH}_2 + \text{H}_2\text{O} \]

**Conclusion**: Aqueous ammonia cannot distinguish between benzoic acid and phenol as both react to form different products but do not provide a clear distinction.

### Final Conclusion
The reagents that can distinguish between benzoic acid and carbolic acid are:
- **Aqueous NaHCO3** (produces effervescence with benzoic acid)
- **Neutral FeCl3** (produces different colored complexes)

### Summary of Correct Options
- Aqueous NaHCO3
- Neutral FeCl3