Question

Assertion (A): Adsorption is an exothermic process. Reason (R): Physisorption of a gas on a solid surface is normally reversible.

• A. Both (A) and (R) are correct and (R) is the correct explanation of (A)
• B. Both (A) and (R) are correct but (R) is not the correct explanation of (A)
• C. (A) is correct but (R) is incorrect
• D. (A) is incorrect but (R) is correct

Hint:

Adsorption is always accompanied by a decrease in surface energy, making it an exothermic process. Physisorption is usually reversible because it involves weak van der Waals forces.

Answer 1

The Correct Option is B

Step 1: Evaluate truth and linkage of A and R.
Adsorption releases energy (exothermic) → A true. Physisorption is reversible (weak forces) → R true. But reversibility doesn't cause exothermicity; energy release comes from bond formation → R not correct explanation.

Step 2: Final Answer:
Both correct but (R) not correct explanation of (A) (option 2).