The document summarizes the electrolysis of brine to produce chlorine, hydrogen gas, and sodium hydroxide. Brine is a concentrated saltwater solution of sodium chloride. During electrolysis of brine, passing an electrical current through the solution decomposes it into chlorine gas and hydrogen gas, along with sodium and hydroxide ions that combine to form sodium hydroxide. This large-scale industrial process produces important chemicals for use in water treatment, manufacturing, and other applications.