Question

The correct thermodynamic conditions for the spontaneous reaction at all temperatures is 

(a) ΔH < 0 and ΔS > 0

(b) ΔH < 0 and ΔS < 0

(c) ΔH < 0 and ΔS < 0

(d) ΔH > 0 and ΔS < 0

Answer 1

The correct option is : (a) ΔH < 0 and ΔS > 0

(c) ΔH < 0 and ΔS < 0

Explanation:

ΔG = ΔH - TΔS

If ΔH < 0 and ΔS > 0

then at all temperatures, ΔG = -ve, spontaneous reaction.

If ΔH < 0 and ΔS = 0

ΔG = (-ve) - T(0) = -ve at all temperatures.