Which one is correct for bond angle?

Options

A. `PF_(3)gtPCl_(3)`
B. `OCl_(2)=ClO_(2)`
C. `NF_(3)gtNH_(3)`
D. `PCl_(3)gtPF_(3)`

Answer

To determine which molecule has the correct bond angle among the given options (PF3, PCl3, OCl2, ClO2, NF3, NH3), we will analyze the molecular structures and the factors affecting bond angles step by step.

### Step-by-Step Solution:

1. **Identify the Central Atom and Structure**:
- For PF3 and PCl3, phosphorus (P) is the central atom in both molecules.
- PF3 has three fluorine (F) atoms and one lone pair on phosphorus, while PCl3 has three chlorine (Cl) atoms and one lone pair on phosphorus.

2. **Electronegativity Consideration**:
- Fluorine is more electronegative than chlorine. The electronegativity values are approximately 4.0 for F and 3.0 for Cl.
- The higher electronegativity of F in PF3 leads to stronger repulsion between the bonded pairs, which increases the bond angle in PF3 compared to PCl3.

3. **Bond Angle Comparison**:
- Due to the stronger repulsion in PF3, it has a larger bond angle than PCl3. Thus, PF3 has a higher bond angle than PCl3.

4. **Analyze OCl2 and ClO2**:
- In OCl2, oxygen is the central atom with two chlorine atoms and two lone pairs.
- In ClO2, chlorine is the central atom with two oxygen atoms and one lone pair.
- The presence of more lone pairs in OCl2 increases electron repulsion, which decreases the bond angle compared to ClO2.

5. **Bond Angle in NF3 and NH3**:
- In NF3, nitrogen is the central atom with three fluorine atoms and one lone pair.
- In NH3, nitrogen is also the central atom with three hydrogen atoms and one lone pair.
- Although fluorine is more electronegative, the geometry of NH3 (with hydrogen) leads to a higher bond angle than NF3 due to the difference in repulsion from the lone pairs and bonded atoms.

6. **Conclusion**:
- From the analysis, we conclude that:
- PF3 has a higher bond angle than PCl3 (Option A is correct).
- ClO2 has a higher bond angle than OCl2.
- NH3 has a higher bond angle than NF3.

### Final Answer:
The correct bond angle comparison is that PF3 has a higher bond angle than PCl3 (Option A).