A closed system consists of two chambers separated by a fixed semipermeable membrane (SPM) which all — Chemical Equilibrium Chemistry Question
Question
A closed system consists of two chambers separated by a fixed semipermeable membrane (SPM) which allows only He(g) to cross it. The left chamber contains NH₄HS(s), NH₃(g), H₂S(g), and He(g) while the right chamber contains only He(g). The entire system is at equilibrium at 300 K. The volume of each chamber is 82.1 L. The total pressure in left chamber is 4 atm and in right chamber, 2 atm. NH₃(g) and H₂S(g) are obtained only from the dissociation of NH₄HS(s). The value of K_p (in atm²) for the reaction: NH₄HS(s) ⇌ NH₃(g) + H₂S(g), is
💡 Solution & Explanation
Since He can cross the SPM, it will reach equilibrium when its partial pressure is equal in both chambers. The right chamber has a total pressure of 2 atm, and since it contains only He, the partial pressure of He throughout the system is 2 atm. In the left chamber, total pressure is 4 atm. Thus, P_NH₃ + P_H₂S = 4 atm - 2 atm = 2 atm. Since NH₃ and H₂S are produced in a 1:1 molar ratio from the dissociation of NH₄HS, P_NH₃ = P_H₂S = 1 atm. K_p = P_NH₃ × P_H₂S = 1 × 1 = 1 atm². Therefore, correct answer is 1.