Final answer:
The equilibrium constant equation for the disproportionation reaction of chlorine with water to form hypochlorous acid, hydronium ions, and chloride ions is K_eq = [HOCl][H3O+][Cl-]/[Cl2].
Step-by-step explanation:
The student asks about the equilibrium constant equation for the disproportionation reaction of gaseous chlorine with water to form hypochlorous acid (HClO), hydronium ions (H3O+), and chloride ions (Cl-). The given equation is Cl2 (aq) + 2H2O(l) → HOCl(aq) + H3O+ (aq) + Cl- (aq).
To write the equilibrium constant (Keq) for the reaction, we use the concentrations of the products over the reactants, not including pure solids or liquids, so the water is excluded. The equilibrium expression for this reaction is Keq = [HOCl][H3O+][Cl-]/[Cl2].