For spontaneous changes in an isolated system (S = entropy)

A. Ds = 0

B. Ds <0

C. Ds > 0

D. Ds = Constant

Answer: Option C

Solution(By Examveda Team)

By second law of thermodynamics the \[TdS \ge \delta Q\]
For an isolated system \[\delta Q = 0\]
\[ \Rightarrow \] for an irreversible (nothing but spontaneous process) \[dS > 0\]   and for an reversible (or the system at equilibrium) \[dS = 0\]