Final answer:
When a reaction reaches equilibrium, the rate of the forward process is equal to the rate of the reverse process. This does not mean that the reaction has stopped or concentrations of reactants and products are equal. Instead, the reaction continues indefinitely with constant concentrations for reactants and products.
Step-by-step explanation:
Based on your question regarding properties that best represent a reaction that has reached equilibrium, the most accurate answer would be option b. The rate of the forward reaction is equal to the rate of the reverse reaction. In chemical equilibrium, the reaction has not 'stopped' but continues to propagate in both the forward and reverse directions at the same speed, giving the illusion of no further changes in the concentration of the reactant and product. However, it's important to clarify that the values of the reactant and product concentrations themselves need not be equal. They just remain constant on reaching equilibrium.
Let's consider the example of the reversible reaction of 204 being consumed and NO2 being produced. As the reaction progresses, the concentration of 204 drops slowing down the reaction in the forward direction. Conversely, as NO2 is produced, it increases, speeding up the reverse reaction. This phenomenon continues until the rates of the forward and backward reaction become equal, marking the establishment of equilibrium.
Learn more about Chemical Equilibrium