Which of the following statements is /are incorrect?

Options

A. physical adsorption at very low temperature and chemisorption occur comparatively at higher temperature
B. The magnitude of chemisorption decreases with rise in temperature and physisorption increases with rise in temperature
C. Chemisorption is irreversible and physiosorption is reversible
D. none of the above

Answer

To determine which of the statements regarding physisorption and chemisorption are incorrect, we will analyze each statement based on the principles of surface chemistry.

### Step-by-Step Solution:

1. **Analyze Statement 1**:
- **Statement**: "Physical adsorption at very low temperature and chemisorption occurs comparatively at high temperature."
- **Analysis**: This statement is correct. Physisorption typically occurs at low temperatures, while chemisorption is favored at higher temperatures due to the energy required to form chemical bonds.

2. **Analyze Statement 2**:
- **Statement**: "The magnitude of chemisorption decreases with rise in temperature and physisorption increases with rise in temperature."
- **Analysis**: This statement is incorrect. Chemisorption generally increases with temperature as the kinetic energy of the molecules increases, allowing for more effective collisions and bond formation. Conversely, physisorption decreases with an increase in temperature because it relies on weak van der Waals forces, which are less effective at higher temperatures.

3. **Analyze Statement 3**:
- **Statement**: "Chemisorption is irreversible and physisorption is reversible."
- **Analysis**: This statement is correct. Chemisorption involves the formation of strong chemical bonds, making it largely irreversible, while physisorption involves weaker van der Waals forces, allowing it to be reversible.

4. **Analyze Statement 4**:
- **Statement**: "None of these."
- **Analysis**: Since we have identified that Statement 2 is incorrect, this statement is also incorrect because it implies that all previous statements are correct.

### Conclusion:
- The incorrect statement is **Option 2**: "The magnitude of chemisorption decreases with rise in temperature and physisorption increases with rise in temperature."

### Final Answer:
The incorrect statement is **Option 2**.