Answer: remain constant.
- A become equal
- B remain constant
- C fall to zero
- D keep increasing
Correct answer: B. remain constant
Explanation: They stay constant with time, though not necessarily equal to one another.
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.