In `PCl_(3)F_(2)` molecules, select the correct statement about two (P-F) bonds:

Options

A. Both (P-F) bonds are equatorial
B. Both (P-F) bonds are axial
C. One (P-F) bond is axial and one (P-F) bond is equatorial
D. can not be predicted

Answer

To solve the question regarding the `PCl3F2` molecule and the characteristics of the two `P-F` bonds, we will follow these steps:

### Step 1: Determine the hybridization of the phosphorus atom in `PCl3F2`.
- The central atom is phosphorus (P), which has a valency of 5.
- The surrounding atoms are 3 chlorine (Cl) atoms and 2 fluorine (F) atoms.
- To find the steric number, we use the formula:
\[ \text{Steric Number} = \text{Number of surrounding atoms} + \text{Number of lone pairs} \]
In this case, there are 5 surrounding atoms (3 Cl + 2 F) and no lone pairs on phosphorus.
- Therefore, the steric number is 5, which indicates that the hybridization is \( sp^3d \).

### Step 2: Determine the molecular geometry of `PCl3F2`.
- With an \( sp^3d \) hybridization and a steric number of 5, the molecular geometry is trigonal bipyramidal.
- In this geometry, there are two types of positions: axial and equatorial.

### Step 3: Assign the positions of the atoms based on electronegativity.
- Among the surrounding atoms, fluorine is more electronegative than chlorine.
- In a trigonal bipyramidal structure, the more electronegative atoms (in this case, fluorine) will occupy the axial positions to minimize repulsion.
- Therefore, the two fluorine atoms will occupy the axial positions, while the three chlorine atoms will occupy the equatorial positions.

### Step 4: Analyze the statements regarding the `P-F` bonds.
- Since both `P-F` bonds are in the axial positions, we can conclude that the statement "both `P-F` bonds are axial" is correct.

### Final Conclusion:
The correct statement about the two `P-F` bonds in `PCl3F2` is that both `P-F` bonds are axial.

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