Answer:
0.0590 M⁻¹
Step-by-step explanation:
Kc represents the equilibrium constant. It is given as;
Kc = [products] / [reactants]
For the reaction; 2SO2(g) + O2(g) <--> 2SO3
Products = SO3
Reactants = SO2 and O2
Kc is given as;
Kc = [SO3]² / [SO2]² [O2]
Kc = 0.120² / (0.860)² (0.330)
Kc = 0.0144 / 0.2440 = 0.0590 M⁻¹