The following equilibrium constants were determined at 1123 K: C (s) + CO2 (g) ⇌ 2CO (g) KC1 = 1.4 × 1012 CO (g) + Cl2 (g) ⇌ COCl2 (g) KC2 = 5.5 × 101 Write the equilibrium constant expression Kc and calculate the equilibrium constant at 1123 K for the following reaction. C (s) + CO2 (g) + 2Cl2 (g) ⇌2COCl2 (g)

The equilibrium constant expression (Kc) for a reaction is the ratio of the concentrations of the products to the concentrations of the reactants, each raised to the power of their stoichiometric coefficients in the balanced chemical equation.

For the first reaction: C (s) + CO2 (g) ⇌ 2CO (g), the equilibrium constant expression is Kc1 = [CO]^2 / [C][CO2]

For the second reaction: CO (g) + Cl2 (g) ⇌ COCl2 (g), the equilibrium constant expression is Kc2 = [COCl2] / [CO][Cl2]

The given reaction is: C (s) + CO2 (g) + 2Cl2 (g) ⇌ 2COCl2 (g)

This reaction is the sum of the first and second reactions multiplied by 2. Therefore, the equilibrium constant for the given reaction (Kc) is the product of the equilibrium constants of the first and second reactions raised to the power of their stoichiometric coefficients.

So, Kc = (Kc1 * Kc2^2) = (1.4 × 10^12 * (5.5 × 10^1)^2) = 1.4 × 10^12 * 3.025 × 10^3 = 4.23 × 10^15

Therefore, the equilibrium constant for the reaction C (s) + CO2 (g) + 2Cl2 (g) ⇌ 2COCl2 (g) at 1123 K is 4.23 × 10^15.