select the correct statement (s) :

Options

A. adsorption is a non - spontyaneous process
B. surface energy deceases during the process of adsorption
C. adsorption takes place with decrease of entropy
D. in general adsoption is exothermic process

Answer

To solve the question regarding the correct statements about adsorption, we will analyze each statement one by one based on the principles of surface chemistry.

### Step-by-Step Solution:

1. **Understanding Adsorption**:
- Adsorption is a process where atoms, ions, or molecules from a gas, liquid, or solid adhere to the surface of another solid or liquid (the adsorbent).
- Example: Oxygen gas (O2) gets adsorbed on activated carbon.

2. **Analyzing the Statements**:
- **Statement A**: "Adsorption is a non-spontaneous process."
- **Analysis**: This statement is incorrect. Adsorption is generally a spontaneous process because it occurs naturally without external force when the adsorbate comes into contact with the adsorbent.

- **Statement B**: "Surface energy decreases during the process of adsorption."
- **Analysis**: This statement is correct. When adsorption occurs, the surface energy of the adsorbent decreases because the adsorbate molecules are bound to the surface, leading to a more stable configuration.

- **Statement C**: "Adsorption takes place with a decrease of entropy."
- **Analysis**: This statement is correct. When gas molecules are adsorbed onto a surface, their freedom of movement is restricted, leading to a decrease in entropy (randomness).

- **Statement D**: "In general, adsorption is an exothermic process."
- **Analysis**: This statement is correct. During adsorption, energy is released as the adsorbate molecules adhere to the surface, making it an exothermic process.

3. **Conclusion**:
- The correct statements regarding adsorption are:
- Statement B: Surface energy decreases during the process of adsorption.
- Statement C: Adsorption takes place with a decrease of entropy.
- Statement D: In general, adsorption is an exothermic process.

### Final Answer:
The correct statements are B, C, and D.

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