The following two gas-phase equilibria are both established at 298 K.
Reaction 1:
PCl₅(g) ⇌ PCl₃(g) + Cl₂(g) K₁ = 1.8 × 10⁻¹
Reaction 2:
H₂(g) + Cl₂(g) ⇌ 2 HCl(g) K₂ = 4.0 × 10³¹
(a)–(d) refer to these data. The universal gas constant is R = 8.314 J·mol⁻¹·K⁻¹.
a) Calculate ΔG° (in kJ·mol⁻¹) for Reaction 1.
b) Calculate ΔG° (in kJ·mol⁻¹) for Reaction 2.
c) Using Reactions 1 and 2, write a balanced overall reaction that produces PCl₃(g) and 2 HCl(g) from PCl₅(g) and H₂(g) only. Show that the corresponding ΔG° for the overall process can be obtained by combining the values from parts (a) and (b).
d) Determine the equilibrium constant K_overall for the combined reaction written in part (c). Comment on whether the overall process is product-favored under standard conditions.