Sodium carbonate is an organic sodium salt and a carbonate salt. Sodium Carbonate is the disodium salt of carbonic acid with alkalizing properties. When dissolved in water, sodium carbonate forms carbonic acid and sodium hydroxide, ideal for detergents to remove unwanted, insoluble stains. Sodium carbonate soaps also help remove insoluble oils from materials, such as motor oils, human sweat stains and vegetable grease.