Question

If an endothermic reaction is non-spontaneous at freezing point of water and becomes feasible at its boiling point then

(A) ΔH is – ve, ΔS is ve 

(B) ΔH and ΔS both are +ve 

(C) ΔH and ΔS both are -ve 

(D) ΔH is ve, ΔS is ve

Answer 1

Correct option (B) ΔH and ΔS both are +ve 

Explanation:

 For a reaction to be spontaneous, ∆G must be negative. According to the equation-

∆G = ∆H −T∆S

If ∆H and ∆S both are positive, than term T. ∆S will be greater than ∆H at high temperature and consequently ∆G will be negative at high temperature.