Identify the incorrect statment for `PCl_5` from the following .

Options

A. In this molecule, orbitals of phosphorous are assumed to undergo `sp^3` d hybridization
B. The geometry of `PCl_5` is trigonal bipyramidal
C. `PCl_5` has two axial bonds stronger than three equatorial bonds.
D. The three equatorial bonds of `PCl_5` lie in a plane.

Explanation

To identify the incorrect statement for \( PCl_5 \), we need to analyze the properties and structure of the molecule. Here’s a step-by-step solution:

### Step 1: Understand the Structure of \( PCl_5 \)
- \( PCl_5 \) has a phosphorus atom at the center surrounded by five chlorine atoms.
- The molecular geometry is trigonal bipyramidal.

**Hint:** Recall that the geometry of a molecule is determined by the arrangement of its electron pairs and atoms.

### Step 2: Determine the Steric Number
- The steric number is calculated by adding the number of atoms bonded to the central atom and the number of lone pairs on the central atom.
- For \( PCl_5 \), phosphorus has 5 chlorine atoms bonded to it and no lone pairs, so the steric number is 5.

**Hint:** The steric number helps in predicting the hybridization and geometry of the molecule.

### Step 3: Identify the Hybridization
- With a steric number of 5, the hybridization of phosphorus in \( PCl_5 \) is \( sp^3d \).

**Hint:** Hybridization can be determined from the steric number using the formula \( s + p + d \) orbitals.

### Step 4: Analyze the Bond Types
- In \( PCl_5 \), there are two types of bonds: axial and equatorial.
- The axial bonds are aligned vertically, while the equatorial bonds are in the same plane.

**Hint:** Understanding the bond types is crucial for analyzing bond lengths and strengths.

### Step 5: Compare Bond Lengths and Strengths
- Axial bonds are typically longer and weaker than equatorial bonds due to increased repulsion from the equatorial bonds.

**Hint:** Consider how bond lengths affect the stability and reactivity of the molecule.

### Step 6: Evaluate the Statements
1. **Statement 1:** Axial bonds are longer and weaker than equatorial bonds. (True)
2. **Statement 2:** Equatorial bonds in \( PCl_5 \) are in the same plane. (True)
3. **Statement 3:** The hybridization of phosphorus in \( PCl_5 \) is \( sp^3d \). (True)
4. **Statement 4:** The steric number of phosphorus in \( PCl_5 \) is 4. (False)

**Hint:** Check each statement against the established properties of \( PCl_5 \).

### Conclusion
The incorrect statement regarding \( PCl_5 \) is that the steric number of phosphorus is 4; it is actually 5.

### Final Answer
The incorrect statement for \( PCl_5 \) is: "The steric number of phosphorus in \( PCl_5 \) is 4."