Select the correct statements .
(i) Physical adsorption is weak, multilayer, non-directional and non-specific.
(ii) Chemical adsorption is strong, unilayer, directional and strong
(iii) Chemical adsorption decreases with temperature
(iv) Chemical adsorption is more stronger than physical adsorption

Options

A. (i) and (iii) only
B. (i), (ii) and (iv) only
C. (iii) only
D. All of these.

Explanation

To solve the question, we need to evaluate each of the given statements about physical and chemical adsorption and determine which ones are correct.

### Step-by-Step Solution:

1. **Evaluate Statement (i)**:
- **Statement**: Physical adsorption is weak, multilayer, non-directional, and non-specific.
- **Analysis**: Physical adsorption, also known as physisorption, involves weak van der Waals forces. It can form multiple layers (multilayer) and is characterized by being non-directional and non-specific.
- **Conclusion**: This statement is **true**.

2. **Evaluate Statement (ii)**:
- **Statement**: Chemical adsorption is strong, unilayer, directional, and strong.
- **Analysis**: Chemical adsorption (chemisorption) involves the formation of strong chemical bonds, is typically unilayer (one layer), and is directional due to the nature of chemical bonding.
- **Conclusion**: This statement is **true**.

3. **Evaluate Statement (iii)**:
- **Statement**: Chemical adsorption decreases with temperature.
- **Analysis**: In fact, chemical adsorption generally increases with temperature because higher temperatures provide more energy for the formation of chemical bonds.
- **Conclusion**: This statement is **false**.

4. **Evaluate Statement (iv)**:
- **Statement**: Chemical adsorption is stronger than physical adsorption.
- **Analysis**: This is true because chemical adsorption involves the formation of strong bonds, whereas physical adsorption involves weaker van der Waals forces.
- **Conclusion**: This statement is **true**.

### Final Evaluation:
Based on the analysis:
- Statement (i) is true.
- Statement (ii) is true.
- Statement (iii) is false.
- Statement (iv) is true.

Thus, the correct statements are (i), (ii), and (iv). Therefore, the correct option is **B: 1, 2, and 4 only**.