Which is not correct regarding the adsorption of a gas on surface of a solid?

Options

A. On increasing temperature adsorption increases continuously
B. Enthalpy and entropy change is negative
C. Adsorption is more for some specific substance
D. Reversible

Explanation

To determine which statement is not correct regarding the adsorption of a gas on the surface of a solid, we will analyze the options one by one.

### Step 1: Understand the Process of Adsorption
Adsorption is the process where gas molecules adhere to the surface of a solid. This process can be either physisorption (weak van der Waals forces) or chemisorption (strong chemical bonds).

### Step 2: Analyze the First Option
The first option states that "on increasing temperature, adsorption increases continuously."

- **Analysis**: Adsorption is typically an exothermic process, meaning it releases heat. According to Le Chatelier's principle, if the temperature increases, the equilibrium will shift to favor the endothermic direction (the reverse process). Therefore, as temperature increases, the amount of gas adsorbed on the solid surface will decrease.

### Conclusion for Step 2:
Thus, the statement that "on increasing temperature, adsorption increases continuously" is incorrect.

### Step 3: Analyze the Second Option
Next, we would analyze the second option regarding the enthalpy of adsorption.

- **Hypothetical Analysis**: If the second option states something along the lines of "the enthalpy of adsorption is positive," we would recognize that for exothermic processes, the enthalpy change (ΔH) is negative, indicating that heat is released when the gas is adsorbed.

### Conclusion for Step 3:
If the second option suggests that the enthalpy of adsorption is positive, this would also be incorrect.

### Final Conclusion:
After analyzing the options, we conclude that the first option is indeed incorrect regarding the adsorption of a gas on the surface of a solid.

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