Identify the correct statement regarding a spontaneous process
- (A)For a spontaneous process in an isolated system, the change in entropy is positive✓ Correct
- (B)Endothermic processes are never spontaneous
- (C)Exothermic processes are always spontaneous
- (D)Lowering of energy in the reaction process is the only criterion for spontaneity
Answer: (A)
Solution
The dependable test of spontaneity for an isolated system comes from the second law: the total entropy must rise, so is positive for a spontaneous change. Spontaneity in general is not settled by enthalpy alone, since , so neither a drop in energy nor an exothermic character is on its own the criterion. The sound statement is that in an isolated system a spontaneous process is attended by a positive entropy change.
JEE Main · 2007 · 29 Apr 2007 · Offline · Single correct option