Which of the following statements correctly describes any chemical reaction that has reached equilibrium? (A)The concentrations of products and reactants are equal. (B)The reaction is now irreversible. (C)Both forward and reverse reactions have halted. (D)The rates of the forward and reverse reactions are equal.

Verified step by step guidance

1. Identify the concept of chemical equilibrium, which refers to the state in a chemical reaction where the rates of the forward and reverse reactions are equal, and the concentrations of reactants and products remain constant over time.
2. Evaluate each option in relation to the definition of chemical equilibrium: (A) states that concentrations of products and reactants are equal, which is not necessarily true as equilibrium can be reached at different concentrations.
3. (B) suggests that the reaction is now irreversible, which is incorrect because at equilibrium, both forward and reverse reactions are still occurring.
4. (C) implies that both forward and reverse reactions have halted, which is incorrect as both reactions continue to occur at the same rate at equilibrium.
5. (D) states that the rates of the forward and reverse reactions are equal, which aligns with the definition of chemical equilibrium, making it the correct choice.

Key Concepts

Chemical Equilibrium

Chemical equilibrium occurs in a reversible reaction when the rates of the forward and reverse reactions are equal, resulting in constant concentrations of reactants and products over time. This state does not imply that the concentrations are equal, but rather that they remain stable as the reactions continue to occur in both directions.

Dynamic Nature of Equilibrium

Equilibrium is a dynamic state, meaning that even though the concentrations of reactants and products remain constant, both the forward and reverse reactions are still occurring. This ongoing process allows for the system to respond to changes in conditions, such as concentration or temperature, which can shift the equilibrium position.

Reversibility of Reactions

Not all reactions reach equilibrium; only reversible reactions can do so. In an irreversible reaction, the reactants convert to products without the possibility of reverting back, while reversible reactions can proceed in both directions, allowing for the establishment of an equilibrium state where the rates of the forward and reverse reactions are equal.