Less contributing structure of nitroethene is :

Options

A.
B.
C.
D.

Explanation

To determine the less contributing structure of nitroethene, we need to analyze the resonance structures of the compound. Here’s a step-by-step solution:

### Step 1: Identify the Resonance Structures
Nitroethene has a nitro group (-NO2) attached to an ethene (C=C) structure. The resonance structures can be drawn by moving electrons around the double bond and the nitro group.

### Step 2: Draw the Possible Resonance Structures
1. **Structure A**: The nitro group is attached to one of the carbon atoms of the double bond, with the nitrogen having a positive charge and one of the oxygens having a negative charge.
2. **Structure B**: The double bond between the two carbon atoms is moved to form a bond with the nitrogen, resulting in a positive charge on the carbon and a negative charge on the nitrogen.

### Step 3: Evaluate the Stability of Each Structure
- **Structure A**: This structure has a positive charge on nitrogen (which is less stable) and a negative charge on oxygen (which is more stable). The distribution of charges is favorable as oxygen is more electronegative than nitrogen.
- **Structure B**: This structure has a positive charge on the carbon atom and a negative charge on the nitrogen atom. This arrangement is less stable because carbon is less electronegative than nitrogen, making it less favorable for carbon to hold a positive charge.

### Step 4: Identify the Less Contributing Structure
The less contributing structure is the one that is less stable. In this case, Structure B is less stable due to the unfavorable positive charge on the carbon atom and the negative charge on the nitrogen atom. Additionally, having two positive charges in close proximity leads to repulsion, making this structure less favorable.

### Conclusion
The less contributing structure of nitroethene is the one where the positive charge is on the carbon atom and the negative charge is on the nitrogen atom (Structure B).

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