Sodium hydroxide is a white hygroscopic substance. It is represented by the formula NaOH. It dissolves easily in water and forms a soft, slippery and soapy solution. It has an itchy effect on human tissue. Sodium hydroxide (also called caustic soda or caustic soda) is used in the laboratory to capture acidic gases such as CO2. It is used in the manufacture of many chemicals in industry, artificial silk, soap, paper, paint, detergent industry and oil refineries.