How physical adsorption will be effected by increase in temperature

Options

A. It will decrease
B. It will increase
C. First increase then decrease
D. None of these

Answer

To understand how physical adsorption is affected by an increase in temperature, we can break down the explanation into several steps:

### Step 1: Define Physical Adsorption
Physical adsorption, also known as physisorption, is the process where gas molecules adhere to the surface of a solid due to weak van der Waals forces. This process is generally reversible and occurs at lower temperatures.

**Hint:** Remember that physical adsorption involves weak intermolecular forces.

### Step 2: Determine the Nature of the Process
Physical adsorption is an exothermic process, meaning that it releases heat when molecules adhere to the surface. When gas molecules come close to the surface, energy is released as they form interactions with the solid.

**Hint:** Exothermic processes release heat, which is crucial for understanding the effect of temperature.

### Step 3: Apply Le Chatelier's Principle
According to Le Chatelier's Principle, if a system at equilibrium is subjected to a change in temperature, the system will adjust to counteract that change. Since physical adsorption is exothermic, increasing the temperature will shift the equilibrium to favor the reactants (the gas molecules), thus decreasing the extent of adsorption.

**Hint:** Le Chatelier's Principle helps predict how equilibrium shifts with temperature changes.

### Step 4: Analyze the Effect of Temperature Increase
As the temperature increases, the kinetic energy of the gas molecules also increases. This higher energy makes it more difficult for the gas molecules to adhere to the surface, leading to a decrease in the amount of gas that gets adsorbed.

**Hint:** Higher temperature means higher kinetic energy, which can overcome weak forces of attraction.

### Step 5: Conclusion
Therefore, with an increase in temperature, the extent of physical adsorption decreases. This means that the correct answer to the question is that physical adsorption will decrease with an increase in temperature.

**Hint:** Focus on the relationship between temperature and adsorption to summarize the conclusion.

### Final Answer
The extent of physical adsorption decreases with an increase in temperature.