Practice question

Given: For the reaction N₂(g) + O₂(g) <=> 2NO(g), K_c = 0.1 at 2000 K. If 0.5 mol of N₂ and 0.5 mol of O₂ are placed in a 5 L vessel, what is the equilibrium concentration of NO ? These values define the system as per NCERT data. Formula: Initial [N₂] = [O₂] = 0.5 / 5 = 0.1 M. This is standard NCERT relation. Substitution & Calculation: Let [NO] = 2x at equilibrium. Then, [N₂] = [O₂] = 0.1 - x . K_c = frac[NO]²[N₂][O₂] = (2x)²/(0.1 - x)² = 0.1 . 4x²/(0.1 - x)² = 0.1, 2x/0.1 - x = sqrt0.1 approx 0.316 . Solving: 2x = 0.0316 - 0.316x, 2.316x = 0.0316, x approx 0.0136, [NO] = 2x approx 0.027 M. Result: The computed value matches expected outcome and confirms correct choice as per NCERT.