Sodium hydroxide (NaOH) is a solid white alkali salt. It is sold in pellets, flakes, granules and in liquid form. It is most soluble in water, but it is also soluble in ethanol and methanol. It reacts with acidic oxides, such as sulfur dioxide, and it readily absorbs moisture. In 2004, global demand was 51 million tonnes.
In 1807, sodium hydroxide was discovered by Humphrey Day. The first line of sodium hydroxide was produced by treating sodium carbonate with calcium hydroxide in a metathesis reaction. By the late 19th century we began using the chloralkali process which has enabled for quicker and more efficient production time.