Question

Diffusion of a gas in a room is not reversible because:

• A. entropy of a system cannot decrease.
• B. entropy of a system remains constant.
• C. entropy of universe cannot decrease.
• D. None of the above.

Answer 1

The correct option is C entropy of universe cannot decrease.

Every process that occurs naturally is irreversible. Diffusion is a natural process. Gases tend to mix automatically without any mediation in diffusion. Thus, some entropy is generated which can’t be reversed.Diffusion of a gas in a room is not reversible because entropy of universe cannot decrease.