Identify the correct statement regarding a spontaneous process `:`

Options

A. Exothermic reaction are always spontaneous.
B. Endothermic reaction are never spontaneoux.
C. Lowering of energy in the reaction of physical process is the only criterion for spontaneity
D. For a spontaneous process in an isolated system, the change in entropy is always positive

Answer

D

Explanation

In an isolated system, (such as spreading of an ik droplet in a beaker filled with water, and the mixing of two gases when the stopcook is opened), there is no exchange of matter or energy between the system and its surrounding. Thus, we can state that for a spontaneous process in an isolated system. the change in entropy is positive. How ever, if the system is not isolated (such as a cup of hot water), then `Delta S_("universe") gt 0` for a spontaneous process.