The most unlikely resonating structures of pnitrophenoxide ion is :

Options

A.
B.
C.
D.

Answer

To determine the most unlikely resonating structure of the para-nitrophenoxide ion, we will analyze the given options based on the rules of resonance and the valency of the atoms involved.

### Step-by-Step Solution:

1. **Understanding Para-Nitrophenoxide Ion**:
- The para-nitrophenoxide ion is derived from para-nitrophenol by deprotonation (removal of a hydrogen ion). The structure consists of a phenolic ring with a nitro group (–NO2) at the para position and an oxygen atom with a negative charge (–O⁻).

2. **Drawing the Resonating Structures**:
- The para-nitrophenoxide ion can exhibit resonance. The negative charge on the oxygen can delocalize through the aromatic ring and the nitro group.
- Possible resonating structures include:
- Structure 1: O⁻ with a double bond to the carbon, and a double bond between the nitrogen and one of the oxygens in the nitro group.
- Structure 2: The negative charge can shift to the carbon atom adjacent to the oxygen, creating a double bond between the oxygen and the carbon.
- Structure 3: The negative charge can also be delocalized to the nitrogen atom, resulting in a positive charge on the nitrogen.

3. **Evaluating the Given Options**:
- **Option A**: This structure is valid as it maintains the octet rule and shows proper charge separation.
- **Option B**: This structure is also valid as it shows a correct distribution of charges and bonds.
- **Option C**: This structure shows nitrogen with five bonds, which is not possible as nitrogen can only form a maximum of four bonds (due to its tetravalency). This makes it an unlikely resonating structure.
- **Option D**: This structure is valid as it maintains proper bonding and charge distribution.

4. **Conclusion**:
- The most unlikely resonating structure of para-nitrophenoxide ion is **Option C**, as it violates the octet rule for nitrogen.