Which of following statements is false ?

Options

A. (a) Increases of pressure of a gas causes the amount of adsorption to increase
B. (b) Increase of temperature may increase or decrease the amount of adsorption
C. (c) The adsorption may be monolayer or multilayer
D. (d) Particle size of the adsorbent does not affect the amount of adsorption

Answer

To determine which of the statements is false, we will analyze each statement one by one.

### Step 1: Analyze the first statement
**Statement 1:** "Increase of pressure of a gas causes the amount of adsorption to increase."

- **Explanation:** According to adsorption theory, the amount of gas adsorbed on a surface is directly proportional to the pressure of the gas. Therefore, as the pressure increases, the amount of adsorption also increases.
- **Conclusion:** This statement is **true**.

### Step 2: Analyze the second statement
**Statement 2:** "Increase of temperature may increase or decrease the amount of adsorption."

- **Explanation:** Adsorption is generally an exothermic process, meaning it releases heat. As temperature increases, the amount of adsorption typically decreases due to the inverse relationship between adsorption and temperature. However, in the case of chemical adsorption, the initial increase in temperature can lead to an increase in adsorption until the activation energy barrier is overcome, after which it decreases. Thus, this statement holds true in certain contexts.
- **Conclusion:** This statement is **true**.

### Step 3: Analyze the third statement
**Statement 3:** "The adsorption may be monolayer or multilayer."

- **Explanation:** Physical adsorption can lead to multilayer formation due to weak van der Waals forces, while chemical adsorption typically results in a monolayer because it involves the formation of strong chemical bonds.
- **Conclusion:** This statement is **true**.

### Step 4: Analyze the fourth statement
**Statement 4:** "Particle size of the adsorbent does not affect the amount of adsorption."

- **Explanation:** The particle size of the adsorbent can significantly influence the surface area available for adsorption. Smaller particles have a larger surface area, which can enhance the amount of adsorption. Therefore, this statement is incorrect.
- **Conclusion:** This statement is **false**.

### Final Conclusion
The false statement among the given options is: **"Particle size of the adsorbent does not affect the amount of adsorption."**

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