Question

Assertion : Work done during free expansion of an ideal gas whether reversible or irreversible is positive.
Reason : During free expansion, external pressure is always less than the pressure of the system.

• 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

Answer 1

Answer: (D)

During the free expansion, in vacuum $P_{ex} = 0$. Hence, no work is done whether the process is reversible or irreversible.