The acid which reduces Fehling solution is

Options

A. Methanoic acid
B. Ethanoic acid
C. Butanoic acid
D. Propanoic acid

Answer

To determine which acid reduces Fehling's solution, we need to identify the acid that contains an aldehyde functional group, as Fehling's solution is specifically used to test for aldehydes.

### Step-by-Step Solution:

1. **Understanding Fehling's Solution**:
- Fehling's solution is a chemical reagent used to test for the presence of aldehydes. It contains copper(II) ions, which act as a weak oxidizing agent. When an aldehyde is present, it reduces the copper(II) ions to copper(I) oxide (Cu2O), resulting in a red precipitate.

2. **Identifying the Functional Group**:
- Aldehydes have the functional group -CHO. Therefore, we need to look for an acid that contains this functional group.

3. **Analyzing the Given Acids**:
- The options provided include:
- A) Methanoic acid (HCOOH)
- B) Ethanoic acid (CH3COOH)
- C) Butanoic acid (C3H7COOH)
- D) Propanoic acid (C2H5COOH)

4. **Checking Each Option**:
- **Methanoic acid (HCOOH)**: This acid contains the aldehyde group (-CHO) and can reduce Fehling's solution.
- **Ethanoic acid (CH3COOH)**: This is a carboxylic acid and does not contain an aldehyde group.
- **Butanoic acid (C3H7COOH)**: This is also a carboxylic acid and lacks the aldehyde group.
- **Propanoic acid (C2H5COOH)**: Similar to the others, this is a carboxylic acid without an aldehyde group.

5. **Conclusion**:
- Among the given options, only methanoic acid (HCOOH) contains the aldehyde functional group and is capable of reducing Fehling's solution. Therefore, the correct answer is **A) Methanoic acid**.