Hybridisation of central atom changes for which of the following molecule when undergoes dimerization?

Options

A. `CF_3`
B. `CIO_3`
C. `NO_2`
D. All of these

Answer

To determine which molecule's central atom undergoes a change in hybridization upon dimerization, we will analyze the hybridization states of the central atoms in the given molecules before and after dimerization.

### Step-by-Step Solution:

1. **Identify the Molecules**:
We need to analyze the hybridization of the central atom in the following molecules:
- CF3
- ClO3
- NO2

2. **Analyze CF3**:
- **Before Dimerization**:
- The carbon atom in CF3 forms three sigma bonds with fluorine atoms and has one unpaired electron.
- The hybridization state can be determined by the number of sigma bonds:
- Hybridization = sp² (3 sigma bonds).
- **After Dimerization**:
- When CF3 dimerizes, it forms C2F6, where the carbon atoms now form four sigma bonds each.
- Hybridization = sp³ (4 sigma bonds).
- **Change in Hybridization**: Yes, from sp² to sp³.

3. **Analyze ClO3**:
- **Before Dimerization**:
- The chlorine atom in ClO3 forms three sigma bonds with oxygen (one double bond and two single bonds) and has one unpaired electron.
- Hybridization = sp² (3 sigma bonds).
- **After Dimerization**:
- When ClO3 dimerizes, it forms Cl2O6, where chlorine forms four sigma bonds (three with oxygen and one with another chlorine).
- Hybridization = sp³ (4 sigma bonds).
- **Change in Hybridization**: Yes, from sp² to sp³.

4. **Analyze NO2**:
- **Before Dimerization**:
- The nitrogen atom in NO2 forms two sigma bonds (one with each oxygen) and has one lone pair.
- Hybridization = sp² (2 sigma bonds + 1 lone pair).
- **After Dimerization**:
- When NO2 dimerizes, it forms N2O4. In N2O4, nitrogen forms two sigma bonds with oxygen and a nitrogen-nitrogen bond.
- Hybridization = sp (2 sigma bonds).
- **Change in Hybridization**: Yes, from sp² to sp.

5. **Conclusion**:
- All three molecules (CF3, ClO3, and NO2) exhibit a change in hybridization upon dimerization.
- Therefore, the answer to the question is that the hybridization of the central atom changes for all the given molecules upon dimerization.

### Final Answer:
The hybridization of the central atom changes for all of the following molecules when they undergo dimerization: CF3, ClO3, and NO2.