Answer:
PCl₅(g) + heat ↔ PCl₃(g) + Cl₂(g)
On increasing the concentration of PCl5(g), the equilibrium will shift in forward direction and produce more PCl₃.
Step-by-step explanation:
According to Le Chatlier's Principle " If we apply any external stress on a system at equilibrium, the system minimize the effect by itself to regain equilibrium". In above reaction initially the system is in equilibrium. when we increase the concentration of reactant (PCl₅), the system goes to forward and produce more product (PCl₃).
After some time reaction will go in backward direction to regain equilibrium position while consuming PCl₃ and Cl₂. Finally reaction will again in equilibrium position.