Sodium hydroxide is a chemical known as caustic soda. It is an inorganic compound whose chemical symbol is NaOH . It is a white solid. It is available in the market in the form of pellets , flakes , granules and various concentrated liquid solutions. Sodium hydroxide dissolves in water and forms a 50% saturated solution. Sodium hydroxide is soluble in water , ethanol and methanol. Its religion is alkaline. This alkali slowly absorbs moisture and carbon dioxide ( CO2) from the air.