Sodium Hydroxide: Handle with Care

Sodium hydroxide is a chemical compound that is foundcommonly in one form or another in households all over the world. Although it can be dangerous, it is very useful in many domestic and commercial applications. It is instrumental in making everything from soap to paper, and even in road construction and hair straightening processes.


Sodium hydroxide is also commonly known as lye or caustic soda, and has been used by humans for thousands of years, most likely first in the processing of animal skins and in making soap. The compound is a strong, highly caustic metallic base that can cause severe chemical burns if it comes in contact with the skin. In its purest form, sodium hydroxide, or NaOH, is a white solid, most often in a powder or in pellets, which needs to be stored in an airtight container since it will absorb water from the air.It dissolves in water with heat, as well as ethanol and methanol.

Home Use

Sodium hydroxide’s domestic uses are various and many. It is used in drain cleaning products, since its causticity can dissolve clogs and blockages. Surfactants that prevent redistribution of solids are added to lye-based solutions for powerful degreasing, such as oven cleaners. The compound was once used at home for straightening hair, but the practice is now confined to professionals in salons, due to the prevalence of caustic burns. It is also used in certain regional foods, but since it is hard to find in a food-quality grade, sodium carbonate is often substituted in recipes now.

Handling of Commercial Sodium Hydroxide

The reaction between sodium carbonate (soda ash) and calcium hydroxide (lime) results in sodium hydroxide, though there are other ways of creating sodium hydroxide.Sodium hydroxide is easiest to transport and manage in an aqueous solution. Care must be taken, as the solution will react with glass and many metals and cause an exothermic (explosive) reaction. Aluminum is a particularly bad choice as sodium hydroxide reacts strongly to aluminum. Iron does not react with sodium hydroxide and is an ideal shipping container.

Unique Uses

The chemical industry utilizes over 50% of the compound produced annually, with the paper industry alone using 25% of that to process wood pulp.Sodium hydroxide is also used in the Bayer process, which is used to manufacture aluminum. Caustic washing of crude oil using sodium hydroxide removes sulfurous impurities, and it is also used in drilling to neutralize gases in rock formations and increase viscosity. Lye is also used during the road construction process, as an underlying layer that absorbs moisture and keeps the oil from asphalt from impinging into groundwater.

Cautions and Hazards

Sodium hydroxide in any form is dangerous if it comes into prolonged contact with the skin. Solid lye in pellet or powder form is inert, but if it gets damp it rapidly becomes corrosive, and can cause debilitating chemical burns to the skin and permanent blindness if the vapor comes in contact with the eyes. Never use lye-based drain cleaner to open clogs in a toilet or plumbing linked to a septic tank, as the reaction between the gases in the tank and the sodium hydroxide can cause a major explosion. Always use gloves and protective eyewear with sodium hydroxide approved for home usage.

Sodium hydroxide is extremely useful in home and commercial applications, but its highly caustic nature and potential to cause damage to property and living tissue. Always be careful and meticulous when handling such powerful chemical compounds.