What is indicated by a Kc value of less than 1?

A Kc value of less than 1 indicates that at equilibrium, the concentration of reactants is greater than that of the products. This implies that the backward reaction, or the reverse reaction, is favored over the forward reaction.

In a chemical equilibrium, Kc is defined as the ratio of the concentrations of the products to the concentrations of the reactants. When Kc is less than 1, it suggests that the numerator (products) is smaller than the denominator (reactants), meaning that at equilibrium, the reactants are more favored.

This understanding aligns with the dynamic nature of chemical equilibria, where reactions can proceed in both the forward and reverse directions until a balance, or equilibrium, is reached. Thus, a Kc value of less than 1 effectively communicates that the system leans towards the reactants, indicating that the reverse reaction is occurring more frequently relative to the forward reaction at equilibrium.