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

### Step-by-Step Solution:

1. **Understanding Resonance:**
- Resonance in chemistry refers to the concept where a single Lewis structure cannot fully describe a molecule. Instead, multiple structures, known as resonating structures, are used to represent the molecule's electron distribution.

2. **Identifying Resonating Structures:**
- For example, in benzene (C6H6), the double bonds between carbon atoms are not fixed but are delocalized. This means that the actual structure of benzene is a hybrid of multiple contributing structures.

3. **Evaluating Statements about Resonance:**
- We need to analyze the statements provided in the question to determine which one is not true about resonance.

4. **Statement Analysis:**
- **Statement 1:** "Resonating structures are hypothetical."
- This is true. Resonating structures are not real; they are a way to visualize electron delocalization.

- **Statement 2:** "Unpaired electrons in the various resonating structures are the same."
- This is also true. The number of unpaired electrons must remain consistent across the resonating structures.

- **Statement 3:** "Hybrid structures are most energetic."
- This statement is not true. In fact, the hybrid structure is the most stable and least energetic form of the molecule, as it represents the average of all resonating structures.

5. **Conclusion:**
- Therefore, the statement that is not true about resonance is: "Hybrid structures are most energetic." This is incorrect because hybrid structures are actually the least energetic.

### Final Answer:
The statement that is not true about resonance is: "Hybrid structures are most energetic."

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