At a definite temperature,the $K_c$ of the following reaction is $0.18$: $PCl_{5(g)} \rightleftharpoons PCl_{3(g)} + Cl_{2(g)}$. In a reaction mixture at the same temperature,$[PCl_3] = 0.042 \ M$,$[Cl_2] = 0.024 \ M$,and $[PCl_5] = 0.005 \ M$. Is this reaction in equilibrium? In which direction will the reaction proceed?

(N/A) The reaction quotient $Q_c$ is calculated as: $Q_c = \frac{[PCl_3][Cl_2]}{[PCl_5]} = \frac{0.042 \times 0.024}{0.005} = 0.2016$.
Since $Q_c = 0.2016$ and $K_c = 0.18$,we observe that $Q_c > K_c$.
Because $Q_c > K_c$,the reaction is not in equilibrium.
To reach equilibrium,the reaction will proceed in the reverse direction (towards the reactants) to decrease the value of $Q_c$ until it equals $K_c$.