How many of these compounds can reduce Tollen's reagent here?
`HCHO, Ph-CHO, Ph-COCH_(3), CH_(3)COCH_(3), CH_(3)-underset(O)underset(||)CH_(2)OH`
Glucose, `CH_(3)CH_(2)OH`

Answer

To determine how many of the given compounds can reduce Tollen's reagent, we need to analyze each compound based on its functional groups. Tollen's reagent is used primarily to test for aldehydes and alpha-hydroxy ketones, as these can reduce the reagent and produce a silver mirror.

### Step-by-step Solution:

1. **Identify the Compounds**:
- HCHO (Formaldehyde)
- Ph-CHO (Benzaldehyde)
- Ph-COCH₃ (Benzophenone)
- CH₃COCH₃ (Acetone)
- CH₃-CHOH-CH₂OH (Glycerol)
- Glucose
- CH₃CH₂OH (Ethanol)

2. **Analyze Each Compound**:
- **HCHO (Formaldehyde)**: This is an aldehyde. Aldehydes can reduce Tollen's reagent. **(Can reduce)**
- **Ph-CHO (Benzaldehyde)**: This is also an aldehyde. It can reduce Tollen's reagent. **(Can reduce)**
- **Ph-COCH₃ (Benzophenone)**: This is a ketone. Ketones generally do not reduce Tollen's reagent. **(Cannot reduce)**
- **CH₃COCH₃ (Acetone)**: This is also a ketone. Ketones do not reduce Tollen's reagent. **(Cannot reduce)**
- **CH₃-CHOH-CH₂OH (Glycerol)**: This compound has an alcohol group and does not have a carbonyl group that can reduce Tollen's reagent. **(Cannot reduce)**
- **Glucose**: Glucose contains an aldehyde group in its open-chain form, which can reduce Tollen's reagent. **(Can reduce)**
- **CH₃CH₂OH (Ethanol)**: This is an alcohol and does not have a carbonyl group. **(Cannot reduce)**

3. **Count the Compounds that Can Reduce Tollen's Reagent**:
- The compounds that can reduce Tollen's reagent are:
- HCHO
- Ph-CHO
- Glucose
- Therefore, there are **3 compounds** that can reduce Tollen's reagent.

### Final Answer:
**3 compounds can reduce Tollen's reagent.**

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