What occurs when carbonate ions react with dilute acid?

When carbonate ions react with dilute acid, effervescence of carbon dioxide gas occurs. This reaction is a characteristic behavior of carbonates when they come into contact with acids. The acid donates protons (H⁺ ions), which lead to the formation of carbonic acid (H₂CO₃) when combined with carbonate ions (CO₃²⁻). Carbonic acid is unstable and quickly decomposes into water (H₂O) and carbon dioxide gas (CO₂), resulting in the characteristic bubbling or fizzing seen during the reaction.

The production of gas is not only a visual indicator of the reaction taking place but also an important aspect when understanding the reactivity of carbonates with acids. This reaction is commonly seen in laboratory settings when testing for the presence of carbonate ions, as the evolution of gas confirms their existence.