Which of the following will not reduce Fehiling's solution ?

Options

A. Formic acid
B. Ethanal
C. 2-Methyl Propanal
D. All will reduce

Answer

To determine which of the given compounds will not reduce Fehling's solution, we need to analyze each compound based on their functional groups and their ability to act as reducing agents. Fehling's solution is a test for aldehydes, which can reduce the copper(II) ions (Cu²⁺) in the solution to copper(I) oxide (Cu₂O), resulting in a red precipitate.

### Step-by-Step Solution:

1. **Identify the Compounds:**
The compounds provided are:
- Formic acid (HCOOH)
- Ethanol (C₂H₅OH)
- 2-Methylpropanol (C₄H₉OH)
- All will reduce

2. **Understanding Fehling's Solution:**
Fehling's solution contains copper(II) ions (Cu²⁺) which are reduced to copper(I) oxide (Cu₂O) by aldehydes. Therefore, we need to identify which of the given compounds can act as an aldehyde or a reducing agent.

3. **Analyzing Each Compound:**
- **Formic Acid (HCOOH):**
Formic acid has the structure H-C(=O)-OH. It contains the aldehyde functional group (CHO), and thus it can reduce Fehling's solution.

- **Ethanol (C₂H₅OH):**
Ethanol has the structure CH₃-CH₂-OH. It is an alcohol and does not contain a carbonyl group (C=O) characteristic of aldehydes. Therefore, ethanol will not reduce Fehling's solution.

- **2-Methylpropanol (C₄H₉OH):**
2-Methylpropanol (also known as tert-butanol) has the structure (CH₃)₃COH. Similar to ethanol, it is also an alcohol and does not have a carbonyl group. Thus, it will not reduce Fehling's solution.

4. **Conclusion:**
Based on the analysis, both ethanol and 2-methylpropanol do not reduce Fehling's solution. However, formic acid does reduce it. Therefore, the correct answer to the question "Which of the following will not reduce Fehling's solution?" is:
- **Ethanol and 2-Methylpropanol** do not reduce Fehling's solution.

### Final Answer:
**Ethanol and 2-Methylpropanol will not reduce Fehling's solution.**