Since you have not included the given reaction, I am going to explain you how to solve these kind of problems.
1) The chemical equilibrium is a dynamic process. It means that in an equilibrim reaction there are two rectaions, the forward reaction and the reverse reaction whose velocities are the same.
2) The general equation of a a chemical reaction in equlibrium is:
aA + bB ⇄ cC + dD
Where A and B are the reactants, C and D are the products, and a, b, c, d, are the coefficientes in the balanced equation.
3) So, the equilibrium law is:
[tex]Keq= \frac{C]^c[D]^d}{[A]^a[B]^b} [/tex]
Where Keq is the constant of equilibrium
4) To complete the explanation, I am going to deal with an example:
i) Consider the equlibrium reaction between hydrogen and iodine:
H₂ (g) + I₂(g) ⇄ 2HI(g)
ii) The forward reaction is H₂ (g) + I₂(g) → 2HI(g)
iii) The reverse reaction is 2HI (g) → H₂ (g) + I₂(g)
iv) The law of equilibrium is:
[tex]Keq= \frac{[HI]^2}{[H_2][I_2]} [/tex]
