Question

Which of the following statements is(are) true? Correct the false statement(s). a. When a reactant is added to a system at equilibrium at a given temperature, the reaction will shift right to reestablish equilibrium. b. When a product is added to a system at equilibrium at a given temperature, the value of \(K\) for the reaction will increase when equilibrium is reestablished. c. When temperature is increased for a reaction at equilibrium, the value of \(K\) for the reaction will increase. d. When the volume of a reaction container is increased for a system at equilibrium at a given temperature, the reaction will shift left to reestablish equilibrium. e. Addition of a catalyst (a substance that increases the speed of the reaction) has no effect on the equilibrium position.

Short answer

Statement a is true only if the added reactant is on the left side of the reaction. Statement b is false; corrected statement: When a product is added to a system at equilibrium at a given temperature, the reaction will shift to reestablish equilibrium but the value of K will remain the same. Statement c is partially true; corrected statement: When the temperature is increased for a reaction at equilibrium, the value of K for an endothermic reaction will increase, and the value of K for an exothermic reaction will decrease. Statement d is false; corrected statement: When the volume of a reaction container is increased for a system at equilibrium at a given temperature, the reaction will shift in the direction of the side with more moles of gas to reestablish equilibrium. Statement e is true.

Step-by-step solution

Statement a

Statement a is true only if the added reactant is on the left side of the reaction. Le Chatelier's principle states that if a change is made to a system at equilibrium, the reaction will shift to minimize the imposed change and reestablish equilibrium. If a reactant is added to the system, the reaction will shift in the direction that uses up the added reactant, which is generally towards the right if the reactant is on the left side of the reaction.

Statement b

Statement b is false. When a product is added to a system at equilibrium, the reaction will shift to reestablish equilibrium, but the equilibrium constant (K) will not change. The value of K is determined by the ratio of the concentrations of products and reactants at equilibrium and is dependent only on temperature. Adding a product will shift the reaction to minimize the imposed change, but it will not change the value of K at a given temperature. Corrected Statement: When a product is added to a system at equilibrium at a given temperature, the reaction will shift to reestablish equilibrium but the value of K will remain the same.

Statement c

Statement c is partially true. When the temperature is increased for a reaction at equilibrium, the value of K for the reaction will change depending on whether the reaction is endothermic or exothermic. For an endothermic reaction, increasing temperature will increase the value of K, while for an exothermic reaction, increasing temperature will decrease the value of K. Corrected Statement: When the temperature is increased for a reaction at equilibrium, the value of K for an endothermic reaction will increase, and the value of K for an exothermic reaction will decrease.

Statement d

Statement d is false. When the volume of a reaction container is increased for a system at equilibrium, the reaction will shift to minimize the change in pressure. According to Le Chatelier's Principle, the reaction will shift in the direction that has more moles of gas to reestablish equilibrium. This can be either left or right, depending on the reaction and the number of moles of gas on each side of the balanced chemical equation. Corrected Statement: When the volume of a reaction container is increased for a system at equilibrium at a given temperature, the reaction will shift in the direction of the side with more moles of gas to reestablish equilibrium.

Statement e

Statement e is true. Adding a catalyst will increase the speed of the reaction to reach equilibrium faster, but it will not affect the position of the equilibrium. A catalyst lowers the activation energy for both the forward and reverse reactions equally, so the equilibrium position remains the same.