At a certain temperature, the equilibrium constant of the reaction: N₂(g) + O₂(g) ⇌ 2NO(g) is 0.0004 — Chemical Equilibrium Chemistry Question

💡 Solution & Explanation

Let total pressure be P. Initial pressures: P_N₂ ≈ 0.8P, P_O₂ ≈ 0.2P. Assuming small conversion, P_N₂ and P_O₂ stay roughly the same. K_p = P_NO² / (0.8P × 0.2P) = 0.0004. P_NO² = 0.0004 × 0.16P² = 64 × 10⁻⁶ P². Thus, P_NO = 8 × 10⁻³ P = 0.008P. Percentage by volume = (P_NO / P) × 100 = 0.8%. Therefore, correct answer is B.