Which of the following is not acceptable as resonating structure :

Options

A. `overset(Theta)CH_(2)-overset(o+)underset(H)underset(|)N=O`
B. `CH_(2)=underset(H)underset(|)N=O`
C. `CH_(2)=overset(o+)underset(H)underset(|)N-O^(Theta)`
D. None of these

Answer

To determine which of the given structures is not an acceptable resonating structure, we need to analyze the bonding and electron distribution in each option. Resonating structures must adhere to certain rules, including the following:

1. **All atoms must have a complete octet** (for second-period elements).
2. **The overall charge must remain the same** in all resonating structures.
3. **Bonds must not exceed the maximum valency** of the atoms involved.

Now, let's analyze the options step-by-step:

### Step 1: Analyze Each Structure
- **Option 1**: Check if all atoms have a complete octet and if the bonding is reasonable.
- **Option 2**: Check for the nitrogen atom. If it has 5 bonds, this violates the octet rule, as nitrogen can only form a maximum of 4 bonds.
- **Option 3**: Check if all atoms have a complete octet and if the bonding is reasonable.
- **Option 4**: Check if all atoms have a complete octet and if the bonding is reasonable.

### Step 2: Identify the Incorrect Structure
- Upon analyzing **Option 2**, we find that nitrogen has 5 bonds. This is not acceptable because nitrogen can only form a maximum of 4 bonds (due to its valency). Therefore, this structure is not a valid resonating structure.

### Conclusion
The structure that is not acceptable as a resonating structure is **Option 2**.

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