Final answer:
When CO2 is added to water, carbonic acid (H2CO3) is formed, which is a weak acid that can dissociate into bicarbonate and carbonate ions.
Step-by-step explanation:
When CO2 is added to water, carbonic acid is formed. The chemical formula for carbonic acid is H2CO3. The reaction can be represented by the equation: CO2 + H2O = H2CO3. Carbonic acid is known to be a weak acid and can further dissociate into bicarbonate (HCO3-) and carbonate (CO32-) ions, depending on the pH of the solution. This process is important in many natural phenomena, including the formation of limestone features like stalactites and stalagmites, as well as in maintaining the pH balance in the blood and the ocean.