Question

1.0 mole of PCl₃ (g) and 2.0 moles of Cl₂ (g) were placed in a 3 litre flask and heated to 400 K. When equilibrium was established, only 0.70 mole of PCl₃ (g) remained. What is the value of equilibrium constant for the reaction: PCl₃ (g) + Cl₂(g) ⇋ PCl₅(g) at 400 K ?

Answer 1

 KC = (0.30)/3/(0.70/3)(1.70/3)

 K_C  =  0.76