What is not true about rasonance?

Options

A. The resonating structures are hypothetical
B. The unpaired electrons in various resonating structures are same
C. Hybrid structure is most energetic
D. Hybrid structure is least energetic

Answer

To determine what is not true about resonance, we will analyze the statements provided regarding resonance structures.

### Step-by-Step Solution:

1. **Identify the Statements**:
We have four statements regarding resonance:
- A: Resonating structures are hypothetical.
- B: The unpaired electrons in various resonating structures are the same.
- C: Hybrid structure is most energetic.
- D: Hybrid structure is least energetic.

2. **Evaluate Statement A**:
- Resonating structures are indeed hypothetical. They are not real structures but rather a way to represent the delocalization of electrons in a molecule.
- **Conclusion**: Statement A is true.

3. **Evaluate Statement B**:
- In resonance structures, the positions of the lone pairs and the unpaired electrons remain the same across the different structures. This means that the unpaired electrons and lone pairs are consistent in all resonating forms.
- **Conclusion**: Statement B is true.

4. **Evaluate Statement C**:
- The hybrid structure, which is a combination of all the resonance forms, is actually the most stable structure, not the most energetic. Stability is inversely proportional to energy; therefore, a more stable structure has lower energy.
- **Conclusion**: Statement C is false.

5. **Evaluate Statement D**:
- Since the hybrid structure is the most stable, it must also be the least energetic. This aligns with the principle that stability corresponds to lower energy.
- **Conclusion**: Statement D is true.

6. **Final Conclusion**:
- The statement that is not true about resonance is **C: Hybrid structure is most energetic**.

### Summary:
The incorrect statement about resonance is that the hybrid structure is the most energetic. In fact, the hybrid structure is the most stable and therefore the least energetic.

---