Final answer:
When more carbonic acid is added to a solution at equilibrium, the system will shift to the left to consume the additional carbonic acid, resulting in an increase in the concentrations of carbon dioxide and water.
Step-by-step explanation:
When more carbonic acid (H2CO3) is added to a solution at equilibrium, the system will shift to the left to consume the additional carbonic acid. This is because the forward reaction of carbonic acid to form carbon dioxide (CO2) and water (H2O) is favored at equilibrium. As a result, the concentrations of carbon dioxide and water will increase, while the concentration of carbonic acid will decrease.