Question

A reaction cannot take place spontaneously at any
temperature when
(a) both ∆H and ∆S are positive
(b) both ∆H and ∆S are negative
(c) ∆H is negative and ∆S is positive
(d) ∆H is positive and ∆S is negative

Answer 1

Explanation:

∆S is the entropy change of the system during the reaction. If ∆S is positive, the system becomes more disordered during the reaction (for instance, when one large molecule splits into several smaller ones). If ∆S is negative, it means the system becomes more ordered.