* Chemical Change: The interaction between carbonic acid (H₂CO₃) and limestone (CaCO₃) results in a chemical reaction that forms new substances. The calcium carbonate in limestone reacts with carbonic acid to form calcium bicarbonate (Ca(HCO₃)₂), which is soluble in water. This reaction changes the chemical composition of the limestone.
* No Physical Breakdown: While the reaction can cause some physical changes, like the formation of caves or sinkholes, the primary process is a chemical transformation of the limestone itself. There is no physical grinding, crushing, or abrasion involved.
In summary: The dissolving of limestone by carbonic acid is a chemical process because it involves a chemical reaction that changes the composition of the limestone.
