Which of the following are hydroxyl acid .

Options

A. Lactic acid
B. Tartaric acid
C. Citric acid
D. Succinic acid

Answer

To determine which of the given compounds are hydroxyl acids, we need to analyze the structures of each compound and check for the presence of a hydroxyl group (-OH) on either the alpha or beta carbon relative to the carboxylic acid group (-COOH).

### Step-by-Step Solution:

1. **Understanding Hydroxyl Acids**:
- Hydroxyl acids are defined as acids that have a hydroxyl group (-OH) attached to either the alpha or beta carbon of the carboxylic acid group.

2. **Analyzing Lactic Acid**:
- Structure: Lactic acid has the formula C3H6O3.
- Structure representation:
```
HO-CH(CH3)-COOH
```
- Here, the carboxylic acid group is at the end, and the hydroxyl group is on the alpha carbon (the carbon adjacent to the carboxylic acid).
- Conclusion: **Lactic acid is a hydroxyl acid.**

3. **Analyzing Tartaric Acid**:
- Structure: Tartaric acid has the formula C4H6O6.
- Structure representation:
```
HOOC-CHOH-CHOH-COOH
```
- In this structure, there are hydroxyl groups on both alpha carbons adjacent to the carboxylic acid groups.
- Conclusion: **Tartaric acid is a hydroxyl acid.**

4. **Analyzing Citric Acid**:
- Structure: Citric acid has the formula C6H8O7.
- Structure representation:
```
HOOC-CHOH-CO-COOH
```
- Here, there is a hydroxyl group on the beta carbon (the second carbon adjacent to the carboxylic acid).
- Conclusion: **Citric acid is a hydroxyl acid.**

5. **Analyzing Succinic Acid**:
- Structure: Succinic acid has the formula C4H6O4.
- Structure representation:
```
HOOC-CH2-CH2-COOH
```
- In this structure, there are no hydroxyl groups on either the alpha or beta carbons adjacent to the carboxylic acid groups.
- Conclusion: **Succinic acid is not a hydroxyl acid.**

### Final Answer:
The compounds that are hydroxyl acids from the given options are:
- Lactic Acid
- Tartaric Acid
- Citric Acid