Question

Considering entropy `(S)` as a thermodynamics parameter, the criterion for the spontaneity of any process is
A. `DeltaS_("system") + DeltaS_("surrounding") gt 0 `
B. `DeltaS_("system") - DeltaS_("surrounding") gt0`
C. `DeltaS_("system") gt 0`
D. `DeltaS_("surrounding") gt 0`

Answer 1

Correct Answer - A
For spontaneous process, `DeltaS` must be positive .
In reversible process
`DeltaS_("system") + DeltaS_("surrounding")=0`
Hence, system is present in equilibrium . (i.e., it is not spontaeous process)
While in irreversible process
`DeltaS_("system") + DeltaS_("surrounding") gt 0`
Hence, in the process `DeltaS` is positive.