Starting with 2 moles SO₂ and 1 mol of O₂ in 1 L flask, the equilibrium mixture required 0.4 moles o — Chemical Equilibrium Chemistry Question

💡 Solution & Explanation

SO₂ is oxidized by MnO₄⁻. The reaction is 5SO₂ + 2MnO₄⁻ + 2H₂O → 5SO₄²⁻ + 2Mn²⁺ + 4H⁺. 0.4 moles of MnO₄⁻ oxidize (5/2) × 0.4 = 1.0 mole of SO₂. Thus, at equilibrium, [SO₂] = 1.0 M. Since initial SO₂ = 2, 1.0 mole reacted. Thus, O₂ reacted = 0.5 mole, and SO₃ formed = 1.0 mole. Eq concentrations: [SO₂]=1.0, [O₂]=0.5, [SO₃]=1.0. K_c = (1)² / ( (1)² × 0.5 ) = 2. Therefore, correct answer is A.