Sodium hydroxide; NaOH; Molar mass 39.9971 g mol. Also known as Sodium oxidanide, Caustic soda, Lye, Ascarite, White caustic, Sodium hydrate. Sodium hydroxide is an inorganic compound, a highly??austic??ase??nd??lkali??hat may cause severe??hemical burns. Highly soluble in??ater, it readily absorbs??oisture??nd??arbon dioxide??hen exposed, as can be seen. It is a widely used chemical in manufacturing processes of wood pulp, ??aper, ??extiles, ??rinking water, ??oaps and detergents. It also has many uses in the food industry and has an E524 number. In the classroom, it is used along with hydrochloric acid and water to explain the pH scale.