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 the hybridization changes of the central atom in the given molecules when they undergo dimerization, we will analyze each molecule step by step.

### Step 1: Analyze CF3
1. **Identify the central atom**: In CF3, the central atom is carbon (C).
2. **Determine the valency of carbon**: Carbon has 4 valence electrons.
3. **Determine the hybridization**: In CF3, carbon forms three sigma bonds with fluorine atoms and has one lone pair. This leads to an sp² hybridization.
4. **Dimerization**: When CF3 dimerizes, two CF3 molecules combine, resulting in a structure where carbon forms four sigma bonds.
5. **New hybridization**: With four sigma bonds, the hybridization changes to sp³.

### Step 2: Analyze ClO3
1. **Identify the central atom**: In ClO3, the central atom is chlorine (Cl).
2. **Determine the valency of chlorine**: Chlorine has 7 valence electrons.
3. **Determine the hybridization**: In ClO3, chlorine forms three sigma bonds with oxygen atoms and has one lone pair, leading to sp² hybridization.
4. **Dimerization**: When ClO3 dimerizes, it forms a structure where chlorine can form four sigma bonds.
5. **New hybridization**: This results in a change to sp³ hybridization.

### Step 3: Analyze NO2
1. **Identify the central atom**: In NO2, the central atom is nitrogen (N).
2. **Determine the valency of nitrogen**: Nitrogen has 5 valence electrons.
3. **Determine the hybridization**: In NO2, nitrogen forms two sigma bonds (one double bond with oxygen and one single bond) and has one unpaired electron, resulting in sp hybridization.
4. **Dimerization**: When NO2 dimerizes, it forms a structure where nitrogen can form three sigma bonds.
5. **New hybridization**: This results in a change to sp² hybridization.

### Conclusion
- **Summary of changes**:
- CF3: sp² to sp³
- ClO3: sp² to sp³
- NO2: sp to sp²

From the analysis, we can conclude that the hybridization of the central atom changes for CF3 and ClO3 when they undergo dimerization, while NO2 changes from sp to sp².

Thus, the correct answer is that the hybridization of the central atom changes for CF3 and ClO3 when they undergo dimerization.

### Final Answer
The hybridization of the central atom changes for CF3 and ClO3 when they undergo dimerization.

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