Which of the following correctly represents the effect of increase of temperature on adsorption ?

Options

A. Chemical adsorption increase regularly wherease physical adsorption first decreases and then increases.
B. Physical adsorption decreases regularly whereas chemical adsorption first increases and then decreases.
C. Chemical adsorption first decrease and then increase whereas physical adsorption shows the opposite trend.
D. Physical adsorption first decreases and then increases whereas chemical adsorption shows the opposite trend.

Explanation

To solve the question regarding the effect of temperature on adsorption, we need to analyze the behavior of both physical adsorption and chemical adsorption (chemisorption) with respect to temperature changes.

### Step-by-Step Solution:

1. **Understanding Adsorption Types**:
- There are two main types of adsorption: **Physical Adsorption** and **Chemical Adsorption (Chemisorption)**.
- Physical adsorption involves weak van der Waals forces, while chemisorption involves the formation of stronger chemical bonds.

2. **Effect of Temperature on Physical Adsorption**:
- As temperature increases, the kinetic energy of the molecules also increases.
- The weak van der Waals forces that hold the adsorbate to the adsorbent can be overcome by this increased kinetic energy.
- Therefore, with an increase in temperature, the rate of physical adsorption **decreases**.

3. **Effect of Temperature on Chemisorption**:
- Initially, as temperature increases, the activation energy for the chemical reactions involved in chemisorption is overcome more easily.
- This leads to an **initial increase** in the rate of chemisorption.
- However, after reaching a certain temperature, the chemical bonds may start to break due to excessive thermal energy, leading to a **decrease** in the rate of chemisorption.
- Thus, the graph of chemisorption rate versus temperature shows an **initial increase followed by a decrease**.

4. **Conclusion**:
- Based on the above analysis:
- For **physical adsorption**, the rate decreases with an increase in temperature.
- For **chemisorption**, the rate initially increases and then decreases after a certain temperature.
- Therefore, the correct representation of the effect of temperature on adsorption is that physical adsorption decreases continuously, while chemisorption first increases and then decreases.

### Final Answer:
The correct option is that physical adsorption decreases with increasing temperature, while chemisorption first increases and then decreases.

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