Question

select the correct answer. what effect does an increase in products have on the reaction rate of a mixture at equilibrium? a. the forward reaction rate increases. b. both the forward and the reverse reaction rates decrease. c. both the forward and the reverse reaction rates increase. d. the reverse reaction rate increases.

Explanation:

To solve this, we use Le Chatelier's principle. At equilibrium, the forward and reverse reaction rates are equal. When the concentration of products increases, the system tries to counteract this change. According to the principle, the system will shift in the direction that consumes the excess products, which is the reverse reaction (since reverse reaction converts products back to reactants). An increase in product concentration increases the frequency of effective collisions for the reverse reaction, so the reverse reaction rate increases. Let's analyze each option:

• Option A: Increasing products does not increase the forward reaction rate; instead, it shifts the equilibrium to favor the reverse reaction, so A is incorrect.
• Option B: The reverse reaction rate should increase, not decrease, so B is incorrect.
• Option C: The forward reaction rate does not increase; only the reverse reaction rate increases to consume the excess products, so C is incorrect.
• Option D: As explained, an increase in products leads to an increase in the reverse reaction rate to consume the excess products, so D is correct.

Answer:

D. The reverse reaction rate increases.