In chemistry, a carbonate is a salt or ester of carbonic acid. Applications To test for the presence of the carbonate anion in a salt, the addition of dilute mineral acid (for example hydrochloric acid) will yield carbon dioxide gas. Carbonate-containing salts are industrially and mineralogically ubiquitous. The term "carbonate" is also commonly used to refer to one of these salts or carbonate minerals. Most common is calcite, or calcium carbonate, the chief constituent of limestone. The proces… (More on Carbonate)