Assertion : Physical adsorption increases with increase in temperature.
Reason : Physical adsorption is an endothermic process.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion.
B. If both assertion and reason are true but reason is not the correct explanation of assertion
C. If assertion is true but reason is false
D. if both assertion and reason are false

Explanation

To solve the question regarding the assertion and reason about physical adsorption, we can break it down into a step-by-step analysis:

### Step 1: Understand Physical Adsorption
Physical adsorption, also known as physisorption, occurs when molecules adhere to a surface due to weak van der Waals forces. This process is characterized by its reversibility and is not specific to any particular type of molecule.

**Hint:** Remember that physical adsorption involves weak forces and is reversible.

### Step 2: Analyze the Assertion
The assertion states that "Physical adsorption increases with increase in temperature." However, based on the principles of physical adsorption, it is known that the process is favored at lower temperatures. As the temperature increases, the kinetic energy of the molecules also increases, making it less likely for them to adhere to the surface.

**Hint:** Consider how temperature affects molecular motion and adsorption.

### Step 3: Analyze the Reason
The reason provided states that "Physical adsorption is an endothermic process." In reality, physical adsorption is an exothermic process, meaning it releases heat. This is because when molecules are adsorbed onto a surface, energy is released as the weak van der Waals forces are formed.

**Hint:** Recall the difference between endothermic and exothermic processes.

### Step 4: Determine the Truth of the Assertion and Reason
Since the assertion is false (physical adsorption does not increase with temperature) and the reason is also false (physical adsorption is exothermic, not endothermic), we conclude that both the assertion and the reason are incorrect.

**Hint:** Compare the definitions of endothermic and exothermic processes to clarify their meanings.

### Conclusion
Based on the analysis, the correct answer is:
**Option D: Both assertion and reason are false.**