Question
when the heat of reaction at constant pressure is -2.5 x 103 cal can entropy change is 7.4 cal deg-1 at 25oC, the reaction is predicted as
reversible
Spontaneous
non -spontaneous
Irreversible
Solution
B.
Spontaneous
For the reaction at constant pressure,
ΔH = - 2.5 x 103 cal
ΔS = 7.4 cal deg-1
∴ ΔG = ΔH -TΔS
= (-)2.5 x 103 - 298 x 7.4
= - 2.5 x 103 - 2205.2
ΔG = - 4705 cal
Hence, reaction is spontaneous.
