Sodium Hydroxide

Sodium Hydroxide, symbol NaOH, sometimes known as caustic soda or lye, a strong metallic base. It is a highly corrosive substance, and can cause severe burns to the skin and damage to the eyes on contact. The dust is harmful if inhaled. It is used widely in industry.

Sodium hydroxide is a white, odourless, crystalline solid. It is stored in an airtight container as it absorbs moisture and carbon dioxide from the air. It is soluble in water (the reaction is highly exothermic) and in alcohol. Sodium hydroxide is available commercially in the form of pellets or sticks, and also in solution.

Sodium hydroxide is a strong base. It reacts with acids such as hydrochloric acid to form a salt and water, in a neutralization reaction:

NaOH (aq) + HCl (aq) ? NaCl (s) + H₂O (l)

It is used in many manufacturing processes, notably in the making of soap, paper, and textiles such as rayon.

Sodium hydroxide is relatively cheap and easy to produce. Industrially, it is chiefly produced as a byproduct in the process of making chlorine by the electrolysis of a solution of sodium chloride.