Which of the following can reduce Tollen's reagent ?

Options

A. `HCOOH`
B. `C_6H_5NHOH`
C. `CH_3CHO`
D. Alll of these

Answer

To determine which of the following compounds can reduce Tollen's reagent, we need to understand what Tollen's reagent is and how it reacts with different organic compounds.

### Step-by-Step Solution:

1. **Understanding Tollen's Reagent**:
Tollen's reagent is a solution of silver nitrate (AgNO3) in ammonia (NH3). It is used to test for aldehydes, which can reduce Ag+ ions to metallic silver, forming a characteristic silver mirror on the inner surface of the test tube.

2. **Identifying the Reducing Agents**:
Aldehydes are known to reduce Tollen's reagent. The general reaction for an aldehyde (RCHO) with Tollen's reagent can be represented as:
\[ RCHO + 2Ag^+ + 2OH^- \rightarrow RCOO^- + 2Ag + 2H2O \]
Here, the aldehyde is oxidized to a carboxylate ion, and silver ions are reduced to metallic silver.

3. **Analyzing the Given Compounds**:
- **Acetaldehyde (CH3CHO)**: This is an aldehyde and will reduce Tollen's reagent.
- **Formic Acid (HCOOH)**: Although it is a carboxylic acid, it can also reduce Tollen's reagent due to its ability to act as a reducing agent.
- **Aniline (C6H5NH2)**: Aniline can also reduce Tollen's reagent under certain conditions, as it can be oxidized to form a corresponding imine or other derivatives.

4. **Conclusion**:
All the compounds mentioned (acetaldehyde, formic acid, and aniline) can reduce Tollen's reagent. Therefore, the answer is that all of these compounds can reduce Tollen's reagent.

### Final Answer:
**All of the above options can reduce Tollen's reagent.**

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