Sodium hydroxide, commonly known as lye or caustic soda, is a strong alkaline compound with the chemical formula NaOH. It is a white, odorless solid that is highly soluble in water, producing a strongly basic solution. Sodium hydroxide is widely used in various industries, including the production of soap, paper, and textiles, as well as in water treatment processes. Due to its caustic nature, sodium hydroxide can cause severe chemical burns and should be handled with care. It is also used in laboratories for pH regulation and as a reagent in chemical reactions. Proper safety measures, such as wearing gloves and goggles, are essential when working with this substance.