Which of the following is wrong`:`

Options

A. Enthalpy ( numerical value ) of physisorption is greater than that of chemisorption
B. Physisorption is not very specific but chomisorption is highly specific
C. Chemisorption takes place at relatively high temperatures
D. In physisorption generally multi`-` molecular layers are formed
on the adsorbent

Explanation

To solve the question, "Which of the following is wrong?" regarding the statements about physisorption and chemisorption, we will analyze each statement one by one.

### Step-by-Step Solution:

1. **Analyze Statement 1**:
- The statement claims that the enthalpy of physisorption is greater than that of chemisorption.
- **Explanation**: Physisorption involves weak Van der Waals forces and has an enthalpy value of about 20 to 40 kJ/mol. In contrast, chemisorption involves stronger chemical bonds and has an enthalpy value of 200 to 400 kJ/mol.
- **Conclusion**: This statement is **false**.

2. **Analyze Statement 2**:
- The statement claims that physisorption is not very specific, but chemisorption is highly specific.
- **Explanation**: Physisorption is non-specific because Van der Waals forces act universally on all adsorbates. Chemisorption is specific because it requires a chemical bond to form between the adsorbate and the adsorbent.
- **Conclusion**: This statement is **true**.

3. **Analyze Statement 3**:
- The statement claims that chemisorption takes place at relatively high temperatures.
- **Explanation**: Chemisorption typically requires higher temperatures to provide the necessary activation energy for chemical bonding. This is known as activated adsorption.
- **Conclusion**: This statement is **true**.

4. **Analyze Statement 4**:
- The statement claims that in physisorption, generally multi-molecular layers are formed on the adsorbent.
- **Explanation**: In physisorption, multiple layers can form due to the weak interactions, while chemisorption usually results in a unimolecular layer due to the formation of strong chemical bonds.
- **Conclusion**: This statement is **true**.

### Final Conclusion:
After analyzing all the statements, we find that the first statement is the only **false** statement. Therefore, the answer to the question is **option number one**.

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