Question

PCl5 (g) ⇌ PCl3 (g) + Cl2 (g)

For the reaction at equilibrium, if the volume of the container is increased, the amount of PCl5 present will


a.

decrease.


b.

stay the same.


c.

triple.


d.

increase.


e.

double

Answer 1

The amount of PCl5 present will increase if the volume of the container is increased, as the equilibrium shifts towards the side with more moles of gas to counteract the pressure change.

Step-by-step explanation:

The question asks about the effect of increasing the volume of the container on the equilibrium concentration of PCl5 in the reaction PCl5 (g) ⇌ PCl3 (g) + Cl2 (g). According to Le Châtelier's Principle, increasing the volume of the reaction container will decrease the pressure, causing the equilibrium to shift towards the side with more moles of gas. In this case, the reaction would shift to the left, toward the reactants, which means the amount of PCl5 will increase.

Analysis of the reaction shows that on the left side of the equation there is one mole of gas (PCl5), while on the right side, there are two moles of gas (PCl3 + Cl2). Increasing the volume causes an equilibrium shift to the side with more moles of gas, in this case, the reactant side, to reestablish equilibrium at a new lower pressure.

Therefore, the correct answer to the question is (d) increase.

Answer 2

The correct answer is (a) decrease.

Step-by-step explanation:

When the volume of the container is increased, the pressure decreases. According to Le Chatelier's principle, the equilibrium will shift in the direction that reduces the effect of the stress. Since the reverse reaction consumes one mole of gas (PCl5) while the forward reaction produces two moles of gas (PCl3 and Cl2), the equilibrium will shift to the left, favoring the reverse reaction. As a result, the amount of PCl5 present will decrease at equilibrium.