Question

If $\Delta S=\frac{q_{rev}}{T}$, then choose the incorrect statement(s).

• A. $\Delta S$ is defined only for reversible process.
• B. For irreversible process and same process taking place reversibly, $\Delta S$ is same.
• C. $\Delta S_{sys}$ is always negative for irreversible process.
• D. None of the above

Answer 1

Answer: (A), (C)

The correct options are
A $\Delta S$ is defined only for reversible process.
C $\Delta S_{sys}$ is always negative for irreversible process.

S is a state function, hence $\Delta S$ will be independent of type of process (reversible / irreversible) for $A\to B.$