Answer: Opposing reactions continue at equal rates.
- A Both reactions have completely stopped
- B Only the forward reaction keeps occurring
- C The measured concentrations keep changing
- D Opposing reactions continue at equal rates
Correct answer: D. Opposing reactions continue at equal rates
Explanation: At equilibrium the forward and reverse reactions continue but at equal rates, so concentrations stay constant.
As the reaction proceeds, reactant concentration falls and product concentration rises until both level off at equilibrium.
Concept context
When forward and reverse reaction rates are equal, equilibrium is reached. Learn about Kc, Kp, Le Chatelier's principle, and acid-base equilibria, including pH, buffer solutions, and solubility product.