The equilibrium constant Kp for the reaction PCl51g2 ∆ PCl31g2 + Cl21g2 is 3.81 * 102 at 600 K and 2.69 * 103 at 700 K.(b) How are the equilibrium amounts of reactants and products affected by (iii) addition of a catalyst?

Verified step by step guidance

1. Understand the role of a catalyst in a chemical reaction: A catalyst is a substance that increases the rate of a chemical reaction without being consumed in the process. It works by providing an alternative reaction pathway with a lower activation energy.
2. Recognize that the catalyst does not affect the equilibrium position: Although a catalyst speeds up both the forward and reverse reactions, it does not change the concentrations of reactants and products at equilibrium.
3. Apply this understanding to the given reaction: For the reaction PCl5(g) ⇄ PCl3(g) + Cl2(g), adding a catalyst will increase the rate at which equilibrium is achieved, but it will not change the equilibrium constant (Kp) or the amounts of PCl5, PCl3, and Cl2 present at equilibrium.
4. Consider the effect of temperature separately: Since the equilibrium constant changes with temperature as shown in the problem statement, any changes in temperature would affect the equilibrium concentrations. However, this is independent of the effects of adding a catalyst.
5. Conclude the effect of a catalyst on the equilibrium amounts: In summary, the addition of a catalyst to the reaction involving PCl5, PCl3, and Cl2 will not alter the equilibrium amounts of these substances but will help the system reach its equilibrium state more quickly.

Key Concepts

Chemical Equilibrium

Chemical equilibrium occurs when the rates of the forward and reverse reactions are equal, resulting in constant concentrations of reactants and products. At this state, the system is dynamic, meaning that reactions continue to occur, but there is no net change in the amounts of substances involved.

Equilibrium Constant (Kp)

The equilibrium constant (Kp) is a numerical value that expresses the ratio of the concentrations of products to reactants at equilibrium, each raised to the power of their coefficients in the balanced equation. It provides insight into the position of equilibrium; a larger Kp indicates a greater concentration of products compared to reactants.

Effect of Catalysts on Equilibrium

A catalyst is a substance that increases the rate of a chemical reaction without being consumed in the process. While it speeds up the attainment of equilibrium, a catalyst does not affect the position of the equilibrium or the equilibrium constant; it simply allows the system to reach equilibrium faster.