As a solid, the alkali is deliquescent and readily absorbs moisture and carbon dioxide from the air. It dissolves easily in water, and makes the water warm when this happens. Sodium hydroxide is used as a solution called lye to make soap. Lye is also used to unclog drains. Its dissolving properties and its ability to easily break surface tension are fundamental for its uses. It works in two ways. First, it combines with grease to make soap. Second, it dissolves hair (which is soluble in any basic solution).
Making sodium hydroxide[change | change source]
Sodium hydroxide can be made (with chlorine and hydrogen) using the chloralkali process. A solution of sodium chloride is electrolyzed and sodium hydroxide is made around the cathode, where water is reduced to hydrogen gas and hydroxide ion. The hydrogen is released and the hydroxide bonds with the sodium to make sodium hydroxide. Special care is required to prepare a solution of sodium hydroxide or NaOH in water because considerable heat is liberated by the exothermic reaction. The solution may splatter or boil.