Answer:
K = [N2] [Cl2]³ / [NCl3]²
Step-by-step explanation:
The equilibrium expression, K, of a reaction:
aA + bB ⇄ cC + dD
Is defined as the ratio between the multiplication of concentrations of products powered to its reaction coefficient and the multiplication of concentrations of reactants powered to its reaction coefficient as follows:
K = [C]^c[D]^d / [A]^a[B]^b
Now, for the reaciton:
2NCl3 ⇄ N2(g) + 3Cl2(g)
K is:
K = [N2] [Cl2]³ / [NCl3]²