①△GΘ = 2×86.6 = 173.2 kJ/mol;
K=exp[-173.2/(0.008314×298.15)] = exp(-69.872) = 4.52×10^-31
②△GΘ = 2×103.6 = 207.2 kJ/mol;
K=exp[-207.2/(0.008314×298.15)] = exp(-83.588) = 4.99×10^-37
③△GΘ = 2×(-16.4) = -32.8kJ/mol;
K=exp[32.8/(0.008314×298.15)] = exp(-13.232) = 5.58×10^5