Answer:
At equilibrium, reactants predominate.
Step-by-step explanation:
For every reaction, the equilibrium constant is defined as the ratio between the concentration of products and reactants. Thus, for the reaction N2 (g) + O2 (g) ⇌ 2NO the expression of its equilibrium constant is:
![Keq = ([NO]^(2))/([O_(2) ][N_(2)])](https://img.qammunity.org/2020/formulas/chemistry/college/nnsdlfsk2vtanzqdqnybqivxp0m3i8gfxd.png)
Since the equilibrium constant is Keq = 4.20x10-31 the concentration of reactants O2 and N2 must be much higher than products to obtain such a small number as 4.20x10-31 at the equilibrium. Hence, at equilibrium reactants predominate.