What does CO3 2- represent?

CO3 2- represents the carbonate ion. It consists of one carbon atom bonded to three oxygen atoms and carries a charge of -2. Carbonate is an important polyatomic ion commonly found in various compounds, including carbonates, carbonic acid, and bicarbonates. In nature, it plays a significant role in buffering systems, particularly in biological and environmental contexts, where it helps maintain pH levels in water and biological systems.

The other options represent different ions: bicarbonate (HCO3-) is related but has an additional hydrogen atom and a different charge, oxalate (C2O4 2-) is a different organic ion that contains two carbon atoms, and chlorate (ClO3-) is a chlorinated ion and bears no relation to carbon. Consequently, understanding the structure and significance of carbonate helps clarify its distinction from these other ions.