Which of the following statements regarding the concept of resonance is not correct?

Options

A. The different resonating structrue of a molecule have fixed arrangement of atomic nuclei
B. The different resonating structrues differ in the arrangement of electrons.
C. None of the individual resonating structrue explains the various characterstics of the molecule.
D. The hybrid structrue have equal contribution from all the resonating structrues.

Explanation

To determine which statement regarding the concept of resonance is not correct, we will analyze each statement one by one based on the principles of resonance in chemistry.

### Step-by-Step Solution:

1. **Understanding Resonance**:
- Resonance is a concept used to describe the delocalization of electrons in molecules where the bonding cannot be expressed by a single Lewis structure. Instead, multiple structures (resonance structures) can represent the same molecule.

2. **Analyzing the Statements**:
- **Statement 1**: "The different resonating structures of a molecule have fixed arrangement of atomic nuclei."
- This statement is **correct**. In resonance structures, the positions of the nuclei remain the same; only the arrangement of electrons changes.

- **Statement 2**: "The different resonating structures differ in arrangement of electrons."
- This statement is also **correct**. Resonance structures feature different arrangements of electrons, which can lead to different bond types and placements of charges.

- **Statement 3**: "None of the individual resonating structures explain the various characteristics of the molecule."
- This statement is **correct**. No single resonance structure can fully describe the properties of the molecule; instead, the actual structure is a hybrid of all possible resonance forms.

- **Statement 4**: "The hybrid structure has equal contribution from all the resonating structures."
- This statement is **incorrect**. The hybrid structure does not necessarily have equal contributions from all resonance structures. Structures with less charge separation or more stable configurations contribute more to the hybrid than those with higher charge separation or less stability.

3. **Conclusion**:
- The statement that is not correct is **Statement 4**: "The hybrid structure has equal contribution from all the resonating structures."

### Final Answer:
The statement regarding the concept of resonance that is not correct is: **"The hybrid structure has equal contribution from all the resonating structures."**

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