Question

An endothermic reaction proceeds in the forward direction. Which of the following statements will be true if the temperature at which the reaction occurs is decreased?
a. The equilibrium constant increases.
b. The reaction shifts toward the products.
c. The concentrations of the products decrease.
d. The equilibrium constant decreases

Answer 1

Answer:

The correct answers are:

c. The concentrations of the products decrease

d. The equilibrium constant decreases

Explanation:

Changes in temperature shift the equilibrium. In this problem, the reaction is endothermic, so it absorbs heat so heat is considered as a reactant:

Reactants + heat ⇒ Products

If the temperature is decreased, the heat is decreased, so reactants are removed from the reaction at equilibrium. According to Le Chaterlier's principle, the system will try to compensate the produced change. If reactants are removed, the systems will form reactants and the equilibrium will shift toward the left (formation of more reactants). In consequence, the amount of products will be decreased.

Thus, acorrect option is: c. The concentrations of the products decrease.

Since the equilibrium constant is given by the ratio of concentration of products over concentration of reactants, if the concentration of products decrease, the equilibrium constant also decreases. So, another correct option is: d. The equilibrium constant decreases.