Question

Which of the following represents a reversible process ? dS < 0 (i) dS = 0 (ii) dS > 0 (ii) dS → 00 (iv)​

Answer 1

Explanation:

ds=0 is a reversible process

Answer 2

ii) dS = 0. Entropy change for the reversible process is zero.

Reversible Process

• A reversible process is defined as the process where the products can be reversed to their previous states without altering the thermodynamic properties.    

The entropy of the Reversible Process

• Entropy is defined as the degree of disorderness of the system.
• The entropy change (dS) does not depend on the path or cycles of the reaction. It is only concerned with the final state and initial state.
• For a reversible process A → B → A, the change in entropy is dS = dS (A → B) + dS (B → A) = 0. Zero entropy change (dS) means that the entropy remained unchanged during the reversible process.

The process, where the final state of the reaction can be reversed to its initial state, is called the reversible process. Entropy, the degree of disorderness, does not change for the reversible process. Therefore, dS = 0, entropy change is zero.