Which statement is correct

Options

A. Physical adsorption is multi -layered nondirectional and non-specific
B. Chemical adsorption is unilayered
C. Chemical adsorption is more stronger than physical adsorption .
D. All the above

Answer

To determine which statement is correct regarding physical and chemical adsorption, we will analyze each statement step by step.

### Step 1: Understanding Physical Adsorption
- **Definition**: Physical adsorption occurs due to Van der Waals forces, which are weak intermolecular forces.
- **Characteristics**:
- It is multilayered: Multiple layers of adsorbate can form on the adsorbent surface.
- It is non-directional: The forces act equally in all directions, meaning the adsorbate can attach to the surface in any orientation.
- It is non-specific: The adsorption does not depend on the specific nature of the adsorbate.

**Conclusion**: The statement about physical adsorption being multilayered, non-directional, and non-specific is correct.

### Step 2: Understanding Chemical Adsorption
- **Definition**: Chemical adsorption involves the formation of chemical bonds between the adsorbate and the adsorbent.
- **Characteristics**:
- It is unilayered: Typically, only one layer of adsorbate forms because the formation of a chemical bond is specific to certain orientations.
- It is directional: The formation of chemical bonds depends on the orientation of the molecules involved.
- It is specific: Chemical adsorption occurs based on the specific interactions between the adsorbate and adsorbent.

**Conclusion**: The statement about chemical adsorption being unilayered is correct.

### Step 3: Comparing Strengths of Adsorption Types
- **Strength**: Chemical adsorption is stronger than physical adsorption because it involves the formation of stronger chemical bonds compared to the weak Van der Waals forces in physical adsorption.

**Conclusion**: The statement that chemical adsorption is stronger than physical adsorption is also correct.

### Step 4: Final Conclusion
- Since all the statements regarding physical and chemical adsorption are correct:
- A: Physical adsorption is multilayered and non-directional and non-specific. (Correct)
- B: Chemical adsorption is unilayered. (Correct)
- C: Chemical adsorption is stronger than physical adsorption. (Correct)
- D: All of the above. (Correct)

Thus, the correct answer is **D: All of the above**.

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