Question Detail
Question
When 0.20 mol of hydrogen gas and 0.15 mol of iodine gas are heated at 450 °C until equilibrium is established, the equilibrium mixture is found to contain 0.26 mol of hydrogen iodide. The equation for the reaction is H₂(g) + I₂(g) ⇌ 2HI(g). What is the correct expression for the equilibrium constant, Kc?
Correct Answer
Option C is the correct answer.
Detailed Explanation
From 2HI = 0.26 mol, moles H₂ reacted = 0.13, I₂ reacted = 0.13. At equilibrium: H₂ = 0.20 - 0.13 = 0.07 mol, I₂ = 0.15 - 0.13 = 0.02 mol. Volume cancels since Δn=0. Kc = [HI]²/([H₂][I₂]) = (0.26)²/(0.07×0.02).
Hint
Determine equilibrium moles of each species, then write the Kc expression.