Least contributing resonating structure of nitroethene is:

Options

A.
B.
C.
D.

Explanation

To determine the least contributing resonating structure of nitroethene, we need to analyze the possible resonating structures and evaluate their stability based on the distribution of charges and the octet rule.

### Step-by-Step Solution:

1. **Identify the Structure of Nitroethene**:
Nitroethene (C2H3NO2) consists of an ethene backbone (C=C) with a nitro group (-NO2) attached to one of the carbon atoms. The general structure can be represented as:
```
H2C=CH-NO2
```

2. **Draw Possible Resonating Structures**:
The nitro group can participate in resonance. The primary structures to consider are:
- Structure 1: The nitro group retains its original form.
- Structure 2: The nitro group can be represented with a positive charge on the nitrogen and a negative charge on one of the oxygen atoms.

3. **Evaluate the Stability of Each Structure**:
- **Structure 1**: This structure has a neutral nitro group and maintains the octet rule for all atoms.
- **Structure 2**: This structure has a positive charge on the nitrogen atom and a negative charge on one of the oxygen atoms. While this structure is valid, having a positive charge on a nitrogen atom can make it less stable, especially if it is adjacent to another positive charge.

4. **Identify the Least Contributing Structure**:
The least stable (and therefore least contributing) resonating structure is the one where there are two positive charges present, which is highly unfavorable. In this case, if we consider a structure where both carbon atoms have a positive charge (which is not typical for stable structures), it would be the least stable.

5. **Conclusion**:
The least contributing resonating structure of nitroethene is the one where there are positive charges on both carbon atoms, making it the least stable option. Therefore, the answer is option C.

### Final Answer:
The least contributing resonating structure of nitroethene is option C.

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