Asforption is accompained by

Options

A. decrease in enthalpy anc increase in entropy
B. increase in enthalpy and increase in entropy
C. decrease in enthalpy and decrease in entropy
D. no change in enthalpy and entropy

Explanation

**Step-by-Step Solution:**

1. **Understanding Adsorption**: Adsorption is the process by which atoms, ions, or molecules from a gas, liquid, or dissolved solid adhere to a surface. This process is distinct from absorption, where a substance is fully taken up into another.

2. **Nature of Adsorption**: The adsorption process is typically exothermic. This means that when a gas molecule adheres to a solid surface, it releases energy in the form of heat.

3. **Change in Enthalpy (ΔH)**: Since adsorption is exothermic, the change in enthalpy (ΔH) for the process is negative. This indicates that energy is released during the adsorption process.

4. **Change in Entropy (ΔS)**: When gas molecules are adsorbed onto a solid surface, the randomness or disorder of the system decreases. This is because the gas molecules, which are free to move, become localized on the surface of the solid. Therefore, the change in entropy (ΔS) is also negative.

5. **Conclusion**: In summary, adsorption is accompanied by a decrease in enthalpy (ΔH < 0) and a decrease in entropy (ΔS < 0).

6. **Final Answer**: The correct statement regarding adsorption is that it is accompanied by a decrease in enthalpy and a decrease in entropy.

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