Choose the correct statement regarding `PCl_(5)`

Options

A. All P-Cl bond lengths are equal
B. `P-Cl_("axial ")` bond lengths is more than `P-Cl_("equitorial")`
C. `P-Cl_("equitorial")` bond lengths are more than `P-Cl_("axial")`
D. `P-Cl_("equitorial")` bond length may be equal or larger than `P-Cl_("axial")`

Answer

To solve the question regarding the correct statement about \( PCl_5 \), we can analyze the molecular structure and bonding characteristics of the compound step by step.

### Step 1: Determine the Structure of \( PCl_5 \)
- \( PCl_5 \) consists of phosphorus (P) as the central atom bonded to five chlorine (Cl) atoms.
- Phosphorus has five valence electrons, and each chlorine atom contributes one electron, resulting in a total of 10 electrons for bonding.

**Hint:** Identify the central atom and count the valence electrons involved in bonding.

### Step 2: Calculate the Steric Number
- The steric number is calculated as the number of bonded atoms plus the number of lone pairs on the central atom.
- In \( PCl_5 \), there are 5 bonded chlorine atoms and no lone pairs on phosphorus, resulting in a steric number of 5.

**Hint:** Remember that the steric number helps determine the molecular geometry.

### Step 3: Identify the Molecular Geometry
- With a steric number of 5, the molecular geometry of \( PCl_5 \) is trigonal bipyramidal.
- In this geometry, three chlorine atoms are in the equatorial plane, and two chlorine atoms are positioned axially.

**Hint:** Visualize the arrangement of atoms in a trigonal bipyramidal structure.

### Step 4: Analyze Bond Angles
- The bond angles between equatorial chlorine atoms are approximately 120 degrees.
- The bond angles between axial and equatorial chlorine atoms are approximately 90 degrees.

**Hint:** Consider how the arrangement of atoms affects the bond angles.

### Step 5: Consider Lone Pair Repulsion
- Each chlorine atom has three lone pairs of electrons, which can cause repulsion.
- The lone pair-lone pair repulsion affects the bond lengths, particularly between axial and equatorial bonds.

**Hint:** Think about how lone pairs influence bond lengths and angles.

### Step 6: Compare Axial and Equatorial Bond Lengths
- Due to the lone pair repulsion, the axial bonds in \( PCl_5 \) are longer than the equatorial bonds. This is because the axial positions experience greater repulsion from the equatorial lone pairs.

**Hint:** Relate the concept of repulsion to the observed bond lengths in the molecule.

### Conclusion
The correct statement regarding \( PCl_5 \) is that the axial bond lengths are longer than the equatorial bond lengths due to lone pair-lone pair repulsion.

**Final Answer:** The correct option is that the \( PCl \) axial bond length is greater than the \( PCl \) equatorial bond length.