Citric Acid
Citric acid is a naturally occurring compound found in many citrus fruits like lemons and limes. Because it is one of the few edible acidic compounds, citric acid is used in many food and drink products. In cosmetics, it is used functionally as an acidulent, chelator, viscosifier, and much more. In water, citric acid reacts with sodium bicarbonate to create the famous and fun fizzing of bath bombs.