In which of the following pairs both molecules do not possess same type of hybridisation?

Options

A. `CH_4` and `H_2O`
B. `PCl_5` and `SF_4`
C. `SF_4` and `XeF_4`
D. `BCl_3` and `NCL_3`

Answer

To determine which pair of molecules does not possess the same type of hybridization, we will analyze the hybridization of each molecule in the given pairs.

### Step-by-Step Solution:

1. **Identify the Molecules and Their Hybridization:**
- We will consider the pairs given in the question. For each molecule, we will determine the hybridization based on the number of sigma bonds and lone pairs.

2. **Analyzing the First Pair: CH₄ and H₂O**
- **CH₄ (Methane):**
- Carbon forms 4 sigma bonds with hydrogen.
- Hybridization = sp³ (4 sigma bonds, no lone pairs).
- **H₂O (Water):**
- Oxygen forms 2 sigma bonds with hydrogen and has 2 lone pairs.
- Hybridization = sp³ (2 sigma bonds + 2 lone pairs).
- **Conclusion:** Both CH₄ and H₂O have sp³ hybridization.

3. **Analyzing the Second Pair: PCl₅ and SF₄**
- **PCl₅ (Phosphorus Pentachloride):**
- Phosphorus forms 5 sigma bonds with chlorine.
- Hybridization = sp³d (5 sigma bonds, no lone pairs).
- **SF₄ (Sulfur Tetrafluoride):**
- Sulfur forms 4 sigma bonds with fluorine and has 1 lone pair.
- Hybridization = sp³d (4 sigma bonds + 1 lone pair).
- **Conclusion:** Both PCl₅ and SF₄ have sp³d hybridization.

4. **Analyzing the Third Pair: XeF₄ and BCl₃**
- **XeF₄ (Xenon Tetrafluoride):**
- Xenon forms 4 sigma bonds with fluorine and has 2 lone pairs.
- Hybridization = sp³d² (4 sigma bonds + 2 lone pairs).
- **BCl₃ (Boron Trichloride):**
- Boron forms 3 sigma bonds with chlorine and has no lone pairs.
- Hybridization = sp² (3 sigma bonds, no lone pairs).
- **Conclusion:** XeF₄ has sp³d² hybridization, while BCl₃ has sp² hybridization. They do not possess the same type of hybridization.

5. **Final Answer:**
- The pair that does not possess the same type of hybridization is **XeF₄ and BCl₃**.