2O₃(g) ⇌ 3O₂(g)
At 300 K, ozone is fifty percent dissociated. The standard free energy change at this temperature and 1 atm pressure is (-) ______ J mol⁻¹ (Nearest integer)
[Given: ln 1.35 = 0.3 and R = 8.3 J K⁻¹ mol⁻¹]
At 300 K, ozone is fifty percent dissociated. The standard free energy change at this temperature and 1 atm pressure is (-) ______ J mol⁻¹ (Nearest integer)
[Given: ln 1.35 = 0.3 and R = 8.3 J K⁻¹ mol⁻¹]
Answer: 747
Solution
At 50% dissociation of 2 moles O₃: initial 2 moles O₃ → at equilibrium 1 mole O₃ and 1.5 moles O₂. Total moles = 2.5. Partial pressures: P(O₃) = (1/2.5) × 1 = 2/5 atm, P(O₂) = (1.5/2.5) × 1 = 3/5 atm. Kₚ = [P(O₂)]³/[P(O₃)]² = (3/5)³/(2/5)² = (27/125)/(4/25) = 27/20 = 1.35. ΔG° = -RT ln Kₚ = -8.3 × 300 × 0.3 = -747 J/mol.
JEE Main · 2022 · 24 Jun 2022 · Shift 1 · Integer answer