Condition where forward and reverse reaction rates are equal.

• A. Equilibrium state
• B. Dynamic equilibrium
• C. Steady state
• D. Homeostasis

Answer: (A)

This question tests chemical equilibrium: when the forward and reverse reaction rates are equal, the system has reached an equilibrium state. At that point, the concentrations of reactants and products stop changing with time, even though both directions of the reaction are still happening. This is the dynamic balance often discussed in chemistry—the molecules are continually converting in both directions, but the net amounts stay constant.

Steady state describes a different situation, usually in a flowing system where a species is constantly produced and removed, so its concentration stays constant but not because forward and reverse rates of a single reaction are equal. Homeostasis is a biological concept about maintaining stable internal conditions, not about chemical reaction rates.