Final answer:
The correct equation for the equilibrium constant K for the reaction COCl2(g) ⇌ CO(g) + Cl2(g) is A. K = [CO][Cl2] / [COCl2].
Step-by-step explanation:
The student's question is about calculating the equilibrium constant for the given reaction: COCl2(g) ⇌ CO(g) + Cl2(g). The correct equation for the equilibrium constant K, for a reaction at chemical equilibrium, is based on the concentrations of the products over the reactants, raised to the power of their stoichiometric coefficients. For this reaction, K is calculated as K = [CO][Cl2] / [COCl2]. Therefore, the correct answer is A. K = [CO][Cl2] / [COCl2].