Which of the following compounds may not exist as enantiomers?

Options

A. `CH_(3)CH(OH)CO_(2)H`
B. `CH_(3)CH_(2)CH(CH_(3))CH_(2)OH`
C. `C_(6)H_(5)CH_(2)CH_(3)`
D. `C_(6)H_(5)CHClCH_(3)`

Explanation

To determine which of the given compounds may not exist as enantiomers, we need to analyze the structures of each compound for the presence of chiral centers. A compound can only exist as enantiomers if it has at least one chiral carbon atom (a carbon atom bonded to four different substituents).

Let's go through the compounds step by step:

1. **Identify the Compounds**:
- A: \( \text{CS}_3 - \text{C}(\text{OH})(\text{H})(\text{COOH}) \)
- B: \( \text{CS}_3 - \text{CH}_2 - \text{C}(\text{H})(\text{CH}_3)(\text{OH}) \)
- C: \( \text{C}_6\text{H}_5 - \text{CH}_2 - \text{CH}_3 \)
- D: \( \text{C}_6\text{H}_5 - \text{CH}(\text{Cl})(\text{H})(\text{CH}_3) \)

2. **Analyze Compound A**:
- Structure: \( \text{CS}_3 - \text{C}(\text{OH})(\text{H})(\text{COOH}) \)
- This compound has a chiral carbon (the central carbon is attached to four different groups: \( \text{OH}, \text{H}, \text{COOH}, \text{CS}_3 \)).
- Conclusion: Compound A can exist as enantiomers.

3. **Analyze Compound B**:
- Structure: \( \text{CS}_3 - \text{CH}_2 - \text{C}(\text{H})(\text{CH}_3)(\text{OH}) \)
- This compound also has a chiral carbon (the central carbon is attached to \( \text{H}, \text{CH}_3, \text{OH}, \text{CH}_2\text{CS}_3 \)).
- Conclusion: Compound B can exist as enantiomers.

4. **Analyze Compound C**:
- Structure: \( \text{C}_6\text{H}_5 - \text{CH}_2 - \text{CH}_3 \)
- This compound does not have any chiral carbon (the carbon atoms are not bonded to four different substituents).
- Conclusion: Compound C cannot exist as enantiomers.

5. **Analyze Compound D**:
- Structure: \( \text{C}_6\text{H}_5 - \text{CH}(\text{Cl})(\text{H})(\text{CH}_3) \)
- This compound has a chiral carbon (the central carbon is attached to \( \text{Cl}, \text{H}, \text{CH}_3, \text{C}_6\text{H}_5 \)).
- Conclusion: Compound D can exist as enantiomers.

6. **Final Answer**: The compound that may not exist as enantiomers is **C**.