In physisorption adsorbent does not show specificity for any particular gas because ……. .

Options

A. involved van der Waals forces are universal
B. gases involved behave like ideal gases
C. enthalphy of adsorption is low
D. it is reversible process

Answer

### Step-by-Step Solution:

1. **Understanding Physisorption**: Physisorption, or physical adsorption, is a process where gas molecules adhere to a solid surface through weak intermolecular forces.

2. **Nature of Forces in Physisorption**: The primary forces involved in physisorption are Van der Waals forces. These forces are relatively weak compared to chemical bonds.

3. **Lack of Specificity**: Since Van der Waals forces are universal and similar in strength for all gases, physisorption does not favor any specific gas over another. This means that the adsorbent can interact with various gases in a similar manner.

4. **Conclusion**: Therefore, the reason why physisorption does not show specificity for any particular gas is that the forces involved (Van der Waals forces) are weak and nearly the same for all gases.

5. **Final Answer**: In physisorption, the adsorbent does not show specificity for any particular gas because the involved Van der Waals forces are universal.