Which of the following statements regarding resonance is `NOT` correct?

Options

A. None of the individual resonating structure explain all characterstics of the molecule
B. The different resonating structures differ in the arrangement of electrons
C. The hybrid structure has equal contribution from all the resonating structures always
D. The different resonating structures of a molecule have fixed arrangement of atomic nuclei

Explanation

To determine which statement regarding resonance is `NOT` correct, let's analyze each option step by step.

### Step 1: Analyze the First Statement
**Statement:** None of the individual resonating structures explain all characteristics of the molecule.

**Analysis:** This statement is true. Individual resonating structures do not fully represent the characteristics of the molecule. For example, in carbon dioxide (CO2), no single structure can account for all properties of the molecule.

### Step 2: Analyze the Second Statement
**Statement:** The different resonating structures differ in the arrangement of electrons.

**Analysis:** This statement is also true. In resonance, the arrangement of electrons changes while the arrangement of atoms remains the same. This is a fundamental characteristic of resonance.

### Step 3: Analyze the Third Statement
**Statement:** The hybrid structure has equal contribution from all resonating structures.

**Analysis:** This statement is NOT correct. The hybrid structure is formed based on the contributions of the resonating structures, but it does not have equal contributions from all. The most stable resonating structures contribute more to the hybrid than the less stable ones.

### Step 4: Analyze the Fourth Statement
**Statement:** The different resonating structures of a molecule have a fixed arrangement of atomic nuclei.

**Analysis:** This statement is true. In resonance, while the electrons may shift, the positions of the atomic nuclei remain fixed.

### Conclusion
From the analysis, the statement that is NOT correct is the third statement: "The hybrid structure has equal contribution from all resonating structures."

### Final Answer
The statement that is NOT correct regarding resonance is: **The hybrid structure has equal contribution from all resonating structures.**

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