Chemical equilibrium constant expression (Kc).

Question

2 NOCl (g) ↔2 NO (g) + Cl2 (g)

Answer 1

2 NOCl (g) ↔2 NO (g) + Cl2 (g)
These are easy to write. Here are the rules.
LHS = left hand side = reactants
RHS = right hand side = products
(x) = concentration of x (or whatever is inside)
Kc = (RHS^y/(LHS)^y
Kc = (NO)^2(Cl2)/(NOCl)^2

In words you do this. The product of the molar concentration of the products of the reaction divided by the product of the molar concentrations of the reactants, each raised to the power indicated by the coefficients in the balanced equation is a constant.