Why is adsorption always exothermic ?

Explanation

**Step-by-Step Solution:**

1. **Definition of Adsorption**:
- Adsorption is the process by which atoms, ions, or molecules from a gas, liquid, or dissolved solid adhere to a surface of a solid or liquid (known as the adsorbent).

2. **Types of Adsorption**:
- There are two main types of adsorption: physisorption (physical adsorption) and chemisorption (chemical adsorption).
- Physisorption involves weak van der Waals forces, while chemisorption involves the formation of chemical bonds.
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