The product is a pure colorless transparent liquid. The relative density is 1.328 - 1.349, the melting point is 318.4 degrees Centigrade, and the boiling point is 1390 degrees Centigrades. Pure liquid caustic soda is called liquid caustic soda, which is a colorless and transparent liquid. The industrial product mostly contains impurities, mainly sodium chloride and sodium carbonate, and sometimes a small amount of iron oxide. When dissolved into a concentrated liquid caustic soda, most of the impurities will float to the surface and can be separated and removed.