Which of the following property is /are changed when OF (odd electron species) undergoes dimerisation ?

Options

A. Magnetic nature
B. Planarity
C. Polarity
D. O-F bond length

Answer

To solve the question regarding the properties that change when the odd electron species OF undergoes dimerization, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Nature of OF**:
- OF (odd electron species) has an unpaired electron, which makes it paramagnetic. This means it is attracted to a magnetic field.

2. **Understand Dimerization**:
- Dimerization is the process where two molecules combine to form a dimer. In this case, two OF molecules will combine to form O2F2.

3. **Magnetic Behavior Change**:
- When OF dimerizes, the unpaired electrons pair up in the dimer (O2F2), resulting in a molecule that has no unpaired electrons. This makes the dimer diamagnetic, meaning it is not attracted to a magnetic field.

4. **Evaluate Other Properties**:
- **Planarity**: The geometric arrangement of the molecules may change, but it does not affect the property in question.
- **Polarity**: The polarity of the molecule may change, but it is not directly related to the dimerization process.
- **Bond Length**: The bond length may vary slightly due to the formation of a new compound, but this is not a primary property that is typically considered in this context.

5. **Conclusion**:
- The primary property that changes when OF undergoes dimerization is its magnetic nature, transitioning from paramagnetic to diamagnetic.

### Final Answer:
The property that changes when OF undergoes dimerization is its magnetic nature.