The reaction pcl3 (g) + cl2 (g) ←-→pcl5 (g) has kp=0.0870 at 300 ∘c. a flask is charged with 0.50atmpcl3, 0.50atmcl2, and 0.20atmpcl5 at this temperature. part a use the reaction quotient to determine the direction the reaction must proceed in order to reach equilibrium.

The question only asks regarding the direction of the equilibrium reaction. The general expression of Kp is:

Kp = [PCl₅]/[PCl₃][Cl₂]

The higher the value of K (greater than 1), the more spontaneous the reaction (favors the product side). Otherwise, it favors the reactant side. Since Kp = 0.087 which is less than 1, the direction favors the forward reaction towards the product side.