... alkaline aqueous solution with alkali all perforating. purely flakes caustic soda is white, there are flakes , bar-shaped , granular, ... the quality is fragile. The solid caustic soda has very strong hygroscopicity. Apt to dissolve it in water ... corroding on fibre , skin , glass , pottery ,etc.. ApplicationCaustic soda is widely used as alkaline desiccant in paper, aluminum smelting ...