Question Detail
Question
For the reaction PCl₅(g) ⇌ PCl₃(g) + Cl₂(g), if the initial concentration of PCl₅ is 2.0 M and at equilibrium x M has dissociated, what is the equilibrium constant Kc in terms of x?
Correct Answer
Option A is the correct answer.
Detailed Explanation
Initial [PCl₅] = 2.0 M. At equilibrium: [PCl₅] = 2 - x, [PCl₃] = x, [Cl₂] = x. Kc = [PCl₃][Cl₂]/[PCl₅] = (x)(x)/(2-x) = x²/(2-x).
Hint
Set up an ICE table to determine equilibrium concentrations in terms of x.