Citric Acid Monohydrate is a common form of citric acid which is shaped like a colorless crystal or white crystal. . Citric Acid Monohydrate is widely used as an acidulant, flavoring and preservative in food and beverages, especially soft drinks. Citric acid monohydrate is the water-containing form of citric acid. This chemical compound has the chemical formula C6H8O7.H2O.