Choose the incorrect statement in respect of physisorption

Options

A. It is not specific in nature
B. It arises because of van der Waals' forces
C. It is irreversible in nature
D. Enthalpy of adsorption is in the range 80-240 kJ `mol^(-1)`

Explanation

To solve the question regarding the incorrect statement in respect of physisorption, we will analyze each statement related to physisorption and determine which one is incorrect.

### Step-by-Step Solution:

1. **Understanding Physisorption**:
- Physisorption refers to the physical adsorption of molecules onto a surface through weak van der Waals forces. It is characterized by low energy interactions.

2. **Analyzing the Statements**:
- **Statement 1**: "Physisorption is not specific in nature."
- This statement is **correct**. Physisorption occurs due to weak van der Waals forces, which are not specific to any particular adsorbate or adsorbent. Any molecule can be adsorbed onto a surface.

- **Statement 2**: "Physisorption is reversible."
- This statement is **correct**. Physisorption is generally reversible because the weak van der Waals forces allow the adsorbed molecules to be easily desorbed without significant energy changes.

- **Statement 3**: "The enthalpy of adsorption for physisorption is in the range of 20 to 40 kilojoules per mole."
- This statement is **correct**. The enthalpy of adsorption for physisorption is indeed low, typically ranging from 20 to 40 kJ/mol, due to the weak interactions involved.

- **Statement 4**: "Physisorption involves strong interactions."
- This statement is **incorrect**. Physisorption involves weak interactions (van der Waals forces), not strong interactions. This is the key point that makes this statement incorrect.

3. **Conclusion**:
- The incorrect statement regarding physisorption is that it involves strong interactions.

### Final Answer:
The incorrect statement in respect of physisorption is: "Physisorption involves strong interactions."

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