NCEA Level 2 Chemistry Practice Exam

When the concentration of products in a chemical equilibrium system is increased, the Le Chatelier's principle comes into play. According to this principle, if a system at equilibrium is disturbed by changing the conditions, the system will shift in a direction that counteracts that change.

In the case of increasing the concentration of products, the system will respond by shifting the equilibrium position to the left. This shift promotes the formation of more reactants in order to reduce the concentration of products. Hence, the result of this shift is an increase in the concentration of reactants, moving the system back toward a state of equilibrium.

The rationale for this response is that systems naturally tend to reach equilibrium, where the rates of the forward and reverse reactions are equal. Therefore, an increase in the products disrupts this balance, and the equilibrium adjusts to restore it. This explains why the correct answer is that the equilibrium shifts to the left, thereby resulting in an increase in reactants.