Which of the following statements is/are correct ?

Options

A. Increases of pressure increases the amount of adsorption.
B. Increases of temperature may decreases the amount of adsorption
C. The adsorption may be monolayered or multilayered.
D. Particle size of the adsorbent will not affect the amount of adsorption.

Explanation

To determine which statements regarding adsorption are correct, let's analyze each statement step by step.

### Step 1: Analyze the first statement
**Statement 1:** "Increase of pressure increases the amount of adsorption."

- **Explanation:** Adsorption is a process where gas molecules adhere to the surface of a solid. According to the principles of adsorption, increasing the pressure of a gas increases the number of gas molecules that can come into contact with the adsorbent's surface. This results in a higher amount of gas being adsorbed. Therefore, this statement is correct.

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

- **Explanation:** Adsorption is generally an exothermic process, meaning it releases heat. As temperature increases, the kinetic energy of the gas molecules also increases, which can lead to a decrease in the amount of gas that is adsorbed onto the surface. Therefore, this statement is also correct.

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

- **Explanation:** In physical adsorption (physisorption), multiple layers of adsorbate can form on the adsorbent surface, leading to multilayer adsorption. In contrast, chemical adsorption (chemisorption) typically results in a monolayer because it involves a stronger interaction between the adsorbate and the adsorbent. Therefore, this statement is correct.

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

- **Explanation:** The particle size of the adsorbent does affect the amount of adsorption. Smaller particles have a larger surface area relative to their volume, which allows for more adsorption sites and thus increases the amount of gas that can be adsorbed. Therefore, this statement is incorrect.

### Conclusion
Based on the analysis:
- **Correct Statements:** 1, 2, and 3
- **Incorrect Statement:** 4

### Final Answer
The correct statements are 1, 2, and 3.

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