s - p overlapping is present in

Options

A. `Br_2`
B. `H_2`
C. `O_2`
D. HF

Explanation

To determine where s-p overlapping occurs among the given molecules (Br2, H2, O2, and HF), we can analyze the electronic configurations of the atoms involved in each molecule and identify the type of orbital overlap that takes place during bonding.

### Step-by-Step Solution:

1. **Analyze Br2 (Bromine molecule)**:
- Bromine (Br) has the electronic configuration: 1s² 2s² 2p⁶ 3s² 3p⁵.
- The outermost shell for Br is 4s² 4p⁵.
- In Br2, the unpaired electrons in the 4p orbitals of two bromine atoms overlap.
- **Type of overlap**: P-P overlapping.

2. **Analyze H2 (Hydrogen molecule)**:
- Hydrogen (H) has the electronic configuration: 1s¹.
- In H2, each hydrogen atom has one unpaired electron in the 1s orbital.
- **Type of overlap**: S-S overlapping.

3. **Analyze O2 (Oxygen molecule)**:
- Oxygen (O) has the electronic configuration: 1s² 2s² 2p⁴.
- The outermost shell for O is 2s² 2p⁴.
- In O2, the unpaired electrons in the 2p orbitals of two oxygen atoms overlap.
- **Type of overlap**: P-P overlapping.

4. **Analyze HF (Hydrogen Fluoride)**:
- Hydrogen (H) has the electronic configuration: 1s¹.
- Fluorine (F) has the electronic configuration: 1s² 2s² 2p⁵.
- In HF, the unpaired electron from hydrogen in the 1s orbital overlaps with the unpaired electron in the 2p orbital of fluorine.
- **Type of overlap**: S-P overlapping.

### Conclusion:
The molecule where s-p overlapping occurs is **HF (Hydrogen Fluoride)**.

### Final Answer:
**HF** is the correct answer where s-p overlapping is present.

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