Phosgene (COCl₂) forms from carbon monoxide and chlorine gas according to the equilibrium reaction
CO(g) + Cl₂(g) ⇌ COCl₂(g)
At 330 K, the equilibrium constant expressed in terms of pressure has the value Kp=4.9. A 2.00 L rigid container at 330 K is charged with 0.400 mol of CO, 0.400 mol of Cl₂, and 0.200 mol of COCl₂ and allowed to reach equilibrium.
The container is then rapidly compressed to 1.00 L while the temperature is held constant.
(a) Calculate the partial pressure of each species immediately after the compression but before the system has had time to respond chemically.
(b) Using the pressures from part (a), compute the reaction quotient Qp and determine the direction in which the reaction will proceed to re-establish equilibrium.
(c) Set up a stoichiometric table for the compressed system and determine the equilibrium partial pressure of each species after the system has re-equilibrated in the 1.00 L container.
(d) Determine the ratio of the final total pressure to the initial total pressure (after the first equilibrium but before compression). Explain briefly why this ratio is not exactly equal to the simple geometric compression ratio of 2:1.