Reversible reactions are chemical reactions that can proceed in both the forward and reverse directions. In other words, the reactants can combine to form products, but the products can also react to reform the original reactants. Reversible reactions are denoted by a double arrow (↔) instead of a single arrow (→), which is used for irreversible reactions.
Dynamic equilibrium is a state reached in a reversible reaction when the rates of the forward and reverse reactions are equal, and the concentrations of the reactants and products remain constant over time. It is important to note that dynamic equilibrium does not mean that the reactions have stopped; instead, it indicates that the forward and reverse reactions are occurring at the same rate, resulting in no net change in the concentrations of reactants and products.
At dynamic equilibrium, the concentrations of reactants and products may not be equal, but their relative concentrations remain constant. The equilibrium position of a reversible reaction refers to the relative concentrations of reactants and products at equilibrium. It can be influenced by factors such as temperature, pressure, and the initial concentrations of reactants.
Dynamic equilibrium is a dynamic state because, at the molecular level, the reactant molecules are continuously converting into product molecules and vice versa. The rate of the forward reaction is equal to the rate of the reverse reaction, resulting in a steady state where the macroscopic properties remain constant.
Le Chatelier's principle is often used to describe the behavior of a system at dynamic equilibrium. It states that if a change is imposed on a system in equilibrium, the system will respond in a way that minimizes the effect of the change and restores the equilibrium. For example, if the concentration of a reactant is increased, the equilibrium will shift in the direction that consumes more of that reactant, reducing the concentration and restoring the equilibrium. Similarly, changes in temperature or pressure can cause the equilibrium position to shift to a new state to maintain equilibrium.