Which of the following carboxylic acids is a tricarboxylic acid?

Options

A. Citric acid
B. Malonic acid
C. Succinic acid
D. Malic acid

Answer

To determine which of the given carboxylic acids is a tricarboxylic acid, we need to analyze the structures of each acid and count the number of carboxyl (-COOH) groups present in each.

### Step-by-Step Solution:

1. **Identify the acids**: The options provided are:
- Citric acid
- Malonic acid
- Succinic acid
- Malic acid

2. **Draw the structure of Citric Acid**:
- Citric acid has the following structure:
- It contains three carboxyl groups.
- The structure can be represented as:
```
HOOC-CH2-C(OH)(COOH)-CH2-COOH
```
- Count the carboxyl groups:
- There are 3 carboxyl groups.

3. **Draw the structure of Malonic Acid**:
- Malonic acid has the following structure:
- It contains two carboxyl groups.
- The structure can be represented as:
```
HOOC-CH2-COOH
```
- Count the carboxyl groups:
- There are 2 carboxyl groups.

4. **Draw the structure of Succinic Acid**:
- Succinic acid has the following structure:
- It also contains two carboxyl groups.
- The structure can be represented as:
```
HOOC-CH2-CH2-COOH
```
- Count the carboxyl groups:
- There are 2 carboxyl groups.

5. **Draw the structure of Malic Acid**:
- Malic acid has the following structure:
- It contains two carboxyl groups.
- The structure can be represented as:
```
HOOC-CH(OH)-CH2-COOH
```
- Count the carboxyl groups:
- There are 2 carboxyl groups.

6. **Conclusion**:
- From the analysis, only citric acid contains three carboxyl groups, making it a tricarboxylic acid.
- Therefore, the correct answer is **Citric Acid**.

### Final Answer:
**Citric Acid is the tricarboxylic acid.**