Low temperature is favourable for which type of adsorption ?

Answer

### Step-by-Step Solution:

1. **Understanding Adsorption**:
- Adsorption is the process where particles accumulate on the surface of a solid. The particles that accumulate are called the adsorbate, and the solid surface is known as the adsorbent.

2. **Types of Adsorption**:
- There are two main types of adsorption: physical adsorption (physisorption) and chemical adsorption (chemisorption).
- In physical adsorption, the forces between the adsorbate and adsorbent are weak (like van der Waals forces).
- In chemical adsorption, strong chemical bonds are formed between the adsorbate and adsorbent.

3. **Effect of Temperature on Adsorption**:
- The strength of the bonds formed in physical adsorption is weak, meaning that increasing the temperature can break these bonds, making physical adsorption less favorable at high temperatures.
- Conversely, chemical adsorption requires a certain amount of energy to form strong bonds. Increasing the temperature provides this activation energy, making chemical adsorption more favorable at higher temperatures.

4. **Conclusion**:
- Since physical adsorption is characterized by weak interactions and is less stable at high temperatures, it is favored at low temperatures. Therefore, low temperature is favorable for physical adsorption.

### Final Answer:
Low temperature is favorable for **physical adsorption**.

---