Consider the following reaction at a certain temperature:
PCl₅(g) →PCl₃(g) + Cl₂(g)
K_c = 0.100
At equilibrium,[PCl₅] = 2.00 M and [PCl₃] = [Cl₂] = 1.00 M.If suddenly 1.00 M PCl₅(g) ,PCl₃(g) ,and Cl₂(g) is added,what is the equilibrium concentration of PCl₅(g) ?

Question

Quizplus · Accepted Answer

After adding 1.00 M of each species, the new concentrations are [PCl5] = 3.00 M, [PCl3] = 2.00 M, and [Cl2] = 2.00 M. The reaction quotient Qc = [PCl3][Cl2]/[PCl5] = (2.00)(2.00)/(3.00) = 1.33, which is greater than Kc (0.100). Therefore, the reaction will shift to the left to reach equilibrium, increasing [PCl5]. Solving the equilibrium expression gives [PCl5] = 4.35 M.

Consider the Following Reaction at a Certain Temperature