Which one of the following statements is correct ?

Options

A. Molecular hydrogen is paramagnetic
B. Molecular nitrogen is paramagnetic
C. Molecular oxygen is paramagnetic
D. Molecular oxygen is diamagnetic

Explanation

To determine which statement is correct regarding the magnetic properties of certain molecules, we need to analyze the electronic configurations of the given molecules and identify whether they are paramagnetic or diamagnetic.

### Step-by-Step Solution:

1. **Understanding Paramagnetic and Diamagnetic:**
- **Paramagnetic:** A substance is paramagnetic if it has unpaired electrons in its atomic or molecular orbitals.
- **Diamagnetic:** A substance is diamagnetic if all its electrons are paired.

2. **Analyzing Molecular Hydrogen (H₂):**
- H₂ has 2 electrons.
- Its electronic configuration: \(1s^2\).
- Since both electrons are paired, H₂ is **diamagnetic**.
- **Conclusion:** The statement "Molecular hydrogen is paramagnetic" is **incorrect**.

3. **Analyzing Molecular Nitrogen (N₂):**
- N₂ has 14 electrons.
- Its electronic configuration: \(\sigma 1s^2 \sigma^* 1s^2 \sigma 2s^2 \sigma^* 2s^2 \sigma 2p_x^2 \pi 2p_y^2 \pi 2p_z^2\).
- All electrons are paired in N₂, making it **diamagnetic**.
- **Conclusion:** The statement "Molecular nitrogen is paramagnetic" is **incorrect**.

4. **Analyzing Molecular Oxygen (O₂):**
- O₂ has 16 electrons.
- Its electronic configuration: \(\sigma 1s^2 \sigma^* 1s^2 \sigma 2s^2 \sigma^* 2s^2 \sigma 2p_x^2 \pi 2p_y^2 \pi 2p_z^2 \pi^* 2p_y^1 \pi^* 2p_z^1\).
- There are 2 unpaired electrons in the \(\pi^*\) orbitals, indicating that O₂ is **paramagnetic**.
- **Conclusion:** The statement "Molecular oxygen is paramagnetic" is **correct**.

5. **Analyzing the Fourth Statement:**
- The statement "Molecular oxygen is diamagnetic" contradicts our finding that O₂ is paramagnetic.
- **Conclusion:** This statement is **incorrect**.

### Final Answer:
The correct statement is: **Molecular oxygen is paramagnetic.**