For the reaction at 25∘C N2O4(g)⇌2NO2(g), if ΔG∘f for N2O4 and NO2 are 23.49 and 12.39 KCal.mol−1, then log(Kp) for the reaction is:
-0.9393
N2O4(g)⇌2NO2(g)
△G∘Reaction=2×△G∘formation of NO2−△G∘formation of N2O4
△G∘Reaction=2×(12.39)−(23.49)=1.29 K.Cal.mol−1
△G∘Reaction=−2.303×RT×log(KP)
1.29=−2.303×(2×10−3×298×log(Kp)
log(KP)=−0.9398