columbus school of art and design Sodium hydroxide is amongst the most dangerous chemicals. It is probably the strongest alkaline, known as caustic soda or lye. It is white, odorless and non-volatile in aqueous solutions. It is not readily flammable. However, it is just a highly reactive substance. It forms an exothermic solution with water, evolving heat that might ignite combustible materials nearby. Its reaction along with other metals yields hydrogen gas which ignites within the presence of oxygen. Moreover, fine is quite corrosive.