Formation of `PCl_(3)` is explained on the basis of what hybridisation of phosphorus atom?

Options

A. `sp^2`
B. `sp^3`
C. `sp^3d`
D. `sp^3d^2`

Answer

To determine the hybridization of the phosphorus atom in the formation of \( PCl_3 \), we can follow these steps:

### Step 1: Understand the Structure of \( PCl_3 \)
Phosphorus trichloride (\( PCl_3 \)) consists of one phosphorus atom bonded to three chlorine atoms.

### Step 2: Determine the Valence Electrons
Phosphorus is in Group 15 of the periodic table and has 5 valence electrons. Chlorine is in Group 17 and has 7 valence electrons. In \( PCl_3 \), phosphorus will use 3 of its valence electrons to form bonds with the 3 chlorine atoms.

### Step 3: Calculate the Steric Number
The steric number is calculated by adding the number of bonded atoms to the number of lone pairs on the central atom.

- **Number of bonded atoms**: 3 (from the three \( Cl \) atoms)
- **Number of lone pairs on phosphorus**: Since phosphorus has 5 valence electrons and uses 3 for bonding, it has 2 remaining electrons, which form 1 lone pair.

Thus, the steric number can be calculated as:
\[ \text{Steric Number} = \text{Number of bonded atoms} + \text{Number of lone pairs} = 3 + 1 = 4 \]

### Step 4: Determine the Hybridization
The steric number of 4 corresponds to \( sp^3 \) hybridization. In \( sp^3 \) hybridization, one s orbital and three p orbitals mix to form four equivalent hybrid orbitals, which are arranged in a tetrahedral geometry.

### Conclusion
The hybridization of the phosphorus atom in \( PCl_3 \) is \( sp^3 \).

### Final Answer
The correct hybridization of the phosphorus atom in \( PCl_3 \) is \( sp^3 \).

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