Answer:
4.39
Step-by-step explanation:
Let's consider the following reaction at equilibrium.
2 NH₃(g) ⇄ 3 H₂(g) + N₂(g)
The concentration equilibrium constant (Kc) is the product of the concentration of the products raised to their stoichiometric coefficients divided by the product of the concentration of the reactants raised to their stoichiometric coefficients.
Kc = [H₂]³.[N₂]/[NH₃]²
Kc = (0.700)³.(0.800)/(0.250)²
Kc = 4.39