Liquid oxygen is____ in colour.

Answer

**Step-by-Step Solution:**

1. **Understanding the State of Oxygen:**
- Oxygen exists in different states: gaseous and liquid. In its gaseous form, oxygen is colorless.

2. **Identifying Liquid Oxygen:**
- When oxygen is compressed and cooled to very low temperatures, it transforms into a liquid state, known as liquid oxygen.

3. **Color of Liquid Oxygen:**
- Liquid oxygen is not colorless like its gaseous counterpart. Instead, it exhibits a pale blue color.

4. **Reason for the Color:**
- The pale blue color of liquid oxygen is due to the presence of two unpaired electrons in its molecular structure. These unpaired electrons create magnetic asymmetry.

5. **Absorption of Light:**
- The magnetic asymmetry leads to the absorption of red light from the visible spectrum. When red light is absorbed, the remaining light that is transmitted or reflected gives the liquid oxygen its characteristic pale blue color.

6. **Conclusion:**
- Therefore, the answer to the question is: Liquid oxygen is pale blue in color.

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