Caustic soda - the most common alkali chemical formula NaOH. It turns out the chemical method and by mercury and diaphragm electrolysis of sodium chloride solution. Every year it produces and consumes more than 57 million tons of caustic soda in the world. Caustic soda is available in two types: solid and liquid. Solid caustic soda is a white scaly solid mass with flakes of 0.5-2 cm in size. Caustic soda is very hygroscopic, readily soluble in water, and when connecting it to the water, a large amount of heat. Liquid caustic soda is a kind of colorless or colored liquid.