Formic acid and formaldehyde can not be distinguished by treating with

Options

A. Benedict's soltuion
B. Tollen's reagent
C. Fehling's solution
D. `NaHCO_(3)`

Answer

To solve the question of how formic acid and formaldehyde cannot be distinguished by treating with certain reagents, we will analyze the properties of both compounds and the reactions they undergo with the given reagents.

### Step-by-Step Solution:

1. **Identify the Structures**:
- Formic acid (HCOOH) has the structure:
```
H
|
O=C
|
OH
```
- Formaldehyde (HCHO) has the structure:
```
H
|
O=C
|
H
```

2. **Analyze the Reagents**:
- **Benedict's Solution**: This reagent is used to test for reducing sugars and aldehydes. Both formic acid and formaldehyde contain the aldehyde functional group (C=O), so both will react with Benedict's solution, leading to a positive test.

- **Tollens' Reagent**: This reagent is also used to test for aldehydes. Since both formic acid and formaldehyde are capable of reducing Tollens' reagent, they will both give a positive result.

- **Fehling's Solution**: Similar to the previous two, Fehling's solution tests for the presence of aldehydes. Both compounds will react positively with Fehling's solution due to the presence of the aldehyde group.

3. **NaHCO3 Test**:
- Formic acid is a carboxylic acid and will react with sodium bicarbonate (NaHCO3) to produce carbon dioxide (CO2), water (H2O), and a salt. This reaction can be represented as:
```
HCOOH + NaHCO3 → CO2 + H2O + NaCOO (sodium formate)
```
- Formaldehyde, on the other hand, does not have an acidic hydrogen and will not react with NaHCO3. Therefore, it will not produce CO2 or water.

4. **Conclusion**:
- Formic acid and formaldehyde can be distinguished by the NaHCO3 test, as only formic acid will react and produce gas. However, they cannot be distinguished by Benedict's solution, Tollens' reagent, or Fehling's solution, as both will give positive results with these reagents.

### Final Answer:
Formic acid and formaldehyde cannot be distinguished by treating with **Benedict's solution, Tollens' reagent, and Fehling's solution**.