When the temperature is lowered and pressure is raised, the adsorption of a gas on a solid

Options

A. decreases
B. increases
C. remains unaffected
D. decreases first than increases

Answer

To solve the question regarding the effect of lowering temperature and raising pressure on the adsorption of a gas on a solid, we can follow these steps:

### Step 1: Understand the Concept of Adsorption
Adsorption is the process where molecules of a substance adhere to the surface of a solid or liquid. This results in a higher concentration of the molecules on the surface compared to the bulk of the material.

**Hint:** Remember that adsorption is different from absorption; adsorption involves surface interaction.

### Step 2: Analyze the Effect of Temperature on Adsorption
When the temperature is lowered, the kinetic energy of the gas molecules decreases. This generally leads to an increase in the adsorption process because lower kinetic energy allows gas molecules to be more easily attracted and retained on the surface of the solid.

**Hint:** Think about how temperature affects molecular motion; lower temperature means slower molecules.

### Step 3: Analyze the Effect of Pressure on Adsorption
Increasing the pressure of the gas increases the number of gas molecules that collide with the surface of the solid. According to the principles of adsorption, when pressure is increased, the likelihood of gas molecules being adsorbed onto the surface also increases.

**Hint:** Consider how compressing gas increases its density and thus the number of molecules available for adsorption.

### Step 4: Combine the Effects of Temperature and Pressure
When both temperature is lowered and pressure is raised, the combined effect leads to a significant increase in adsorption. Lowering the temperature enhances the attraction between gas molecules and the solid surface, while raising the pressure increases the number of gas molecules available for adsorption.

**Hint:** Think about how both factors work together to enhance the adsorption process.

### Step 5: Conclusion
Based on the analysis, when the temperature is lowered and the pressure is raised, the adsorption of a gas on a solid increases significantly.

**Final Answer:** The adsorption of a gas on a solid increases.