Dissolution of solid sodium hydroxide in water is a highly exothermic reaction, where a large amount of heat is liberated, posing a threat to safety through the possibility of splashing. The resulting solution is usually colourless and odourless.

Sodium hydroxide 10, 20 and 25% solution is used to manufacture many everyday products, such as paper, aluminium, commercial drain and oven cleaners, and soap and detergents.

Sodium Hydroxide in Water Treatment uses sodium hydroxide to control water acidity and to help remove heavy metals from water. Sodium hydroxide is also used to produce sodium hypochlorite, a water disinfectant.