The impossible resonating structures of fluorobenzene is/are :

Options

A.
B.
C.
D.

Answer

To determine the impossible resonating structures of fluorobenzene, we need to analyze the possible resonance forms and identify which ones are not feasible based on the behavior of the fluorine atom.

### Step-by-Step Solution:

1. **Understanding Fluorobenzene Structure**:
- Fluorobenzene consists of a benzene ring (C6H5) with a fluorine (F) atom attached to one of the carbon atoms.
- The structure can be represented as follows:
```
C
/ \
C C
| |
C - F
| |
C - C
\ /
C
```

2. **Resonance and Electron Donation**:
- Fluorine is an electronegative atom but also has lone pairs that can participate in resonance. It exhibits a +M (mesomeric) effect, meaning it can donate electron density to the aromatic ring.
- Therefore, the resonance structures will involve the movement of electrons from the fluorine to the benzene ring.

3. **Drawing Possible Resonating Structures**:
- **First Resonating Structure**: The original structure of fluorobenzene.
- **Second Resonating Structure**: The double bond between the carbon and fluorine shifts to form a double bond between adjacent carbon atoms, resulting in a positive charge on fluorine.
- **Third Resonating Structure**: The double bond shifts again, creating a new configuration with a positive charge on another carbon and fluorine still carrying a positive charge.
- **Fourth Resonating Structure**: The double bond shifts back to the original position, maintaining the positive charge on fluorine.

4. **Identifying Impossible Structures**:
- In the case of fluorobenzene, any resonance structure that places a negative charge on fluorine is not valid because fluorine cannot stabilize a negative charge due to its high electronegativity.
- Therefore, the structures where fluorine has a negative charge are impossible.

5. **Conclusion**:
- The impossible resonating structures of fluorobenzene are those where fluorine carries a negative charge. Based on the options provided, these are:
- Option C: Fluorine with a negative charge.
- Option D: Fluorine with a negative charge.

### Final Answer:
The impossible resonating structures of fluorobenzene are **Option C and Option D**.