The correct increasing bomnd angle among `BF_(3),PF_(3)` and `CIF_(3)` follow the order

Options

A. `BF_(3) lt PF_(3) lt ClF_(3)`
B. `PF_(3) lt BF_(3) lt ClF_(3)`
C. `ClF_(3) lt PF_(3) lt BF_(3)`
D. `BF_(3)=PF_(3)=ClF_(3)`

Answer

To determine the correct increasing bond angle among BF3, PF3, and ClF3, we will analyze the molecular structures and hybridizations of each compound step by step.

### Step 1: Analyze BF3 (Boron Trifluoride)
- **Valence Electrons**: Boron (B) has 3 valence electrons, and each Fluorine (F) has 7 valence electrons. In BF3, boron forms three bonds with fluorine.
- **Hybridization**: The hybridization of BF3 is sp² because it has three bond pairs and no lone pairs.
- **Molecular Geometry**: The geometry is trigonal planar.
- **Bond Angle**: The bond angle in BF3 is 120°.

### Step 2: Analyze PF3 (Phosphorus Trifluoride)
- **Valence Electrons**: Phosphorus (P) has 5 valence electrons, and each Fluorine (F) has 7 valence electrons. In PF3, phosphorus forms three bonds with fluorine and has one lone pair.
- **Hybridization**: The hybridization of PF3 is sp³ because it has three bond pairs and one lone pair.
- **Molecular Geometry**: The geometry is tetrahedral, but due to the presence of the lone pair, the bond angles are slightly less than the tetrahedral angle (109.5°).
- **Bond Angle**: The bond angle in PF3 is slightly less than 109.5°.

### Step 3: Analyze ClF3 (Chlorine Trifluoride)
- **Valence Electrons**: Chlorine (Cl) has 7 valence electrons, and each Fluorine (F) has 7 valence electrons. In ClF3, chlorine forms three bonds with fluorine and has two lone pairs.
- **Hybridization**: The hybridization of ClF3 is sp³d because it has three bond pairs and two lone pairs.
- **Molecular Geometry**: The geometry is T-shaped due to the presence of the lone pairs.
- **Bond Angle**: The bond angles in ClF3 are less than 90° due to the repulsion from the lone pairs.

### Step 4: Compare the Bond Angles
- **BF3**: 120°
- **PF3**: Slightly less than 109.5°
- **ClF3**: Less than 90°

### Conclusion
The increasing order of bond angles is:
ClF3 < PF3 < BF3

Thus, the correct increasing bond angle among BF3, PF3, and ClF3 follows the order: **ClF3 < PF3 < BF3**.