select thee correct statement (S)

Options

A. physical adsorption is specific in nature
B. chemical adsorption highly specific in nature
C. physical adsorption is due to free valence of atoms
D. chemical adsoption is due to stronger interaction or bond formation

Answer

To solve the question, we need to analyze the statements regarding physical adsorption and chemical adsorption. Let's break down the information provided in the video transcript step by step.

### Step 1: Understand Physical Adsorption
- **Definition**: Physical adsorption, also known as physisorption, involves weak Van der Waals forces between the adsorbate (the substance being adsorbed) and the adsorbent (the surface on which adsorption occurs).
- **Characteristics**:
- It is **non-specific** in nature.
- It can form **multi-layers** of adsorbate on the adsorbent.
- It has **low enthalpy of adsorption**.
- It occurs at **low temperatures**.

### Step 2: Understand Chemical Adsorption
- **Definition**: Chemical adsorption, or chemisorption, involves the formation of strong chemical bonds between the adsorbate and the adsorbent.
- **Characteristics**:
- It is **highly specific** in nature.
- It typically forms a **single layer** of adsorbate on the adsorbent.
- It has **high enthalpy of adsorption**.
- It occurs at higher temperatures compared to physical adsorption.

### Step 3: Analyze Each Statement
1. **Physical adsorption is specific in nature**:
- **Analysis**: This statement is **incorrect**. Physical adsorption is non-specific.

2. **Chemical adsorption is highly specific in nature**:
- **Analysis**: This statement is **correct**. Chemical adsorption is indeed highly specific.

3. **Physical adsorption is due to free valence of atoms**:
- **Analysis**: This statement is **incorrect**. Physical adsorption is due to weak Van der Waals forces, not free valence.

4. **Chemical adsorption is due to strong attraction of bond formation**:
- **Analysis**: This statement is **correct**. Chemical adsorption involves strong chemical bonds.

### Conclusion
Based on the analysis:
- The correct statements are:
- **B**: Chemical adsorption is highly specific in nature.
- **D**: Chemical adsorption is due to strong attraction of bond formation.

### Final Answer
The correct statements are **B** and **D**.

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