What is the process by which sodium hydroxide is prepared?

Sodium hydroxide (NaOH) is prepared commercially by the chlor-alkali process. In this method, electricity is passed through a solution of brine (saltwater). During electrolysis, brine breaks down into chlorine gas (Cl2), hydrogen gas (H2), and sodium hydroxide (NaOH). This process takes place in an electrolytic cell and is one of the most important industrial methods for producing sodium hydroxide.