When electricity is passed through brine(aqueous solution of salt),then H2 Cl2 and NaOH are formed
•Cl2 is formed at anode
•H2 is formed at cathode
NaOH IS nothing but caustic soda and it is known as lye in European countries

Formation of Caustic Soda

Caustic soda, also known as sodium hydroxide (NaOH), is a highly reactive and corrosive compound that is used in a variety of industrial processes. It is commonly used in the production of paper, textiles, and detergents, as well as in the refining of petroleum and the manufacturing of aluminum. Here is a detailed explanation of how caustic soda is formed.

Electrolysis of Salt Water

The most common method of producing caustic soda is through the electrolysis of salt water, also known as brine. This process involves passing an electric current through a solution of salt water, which causes the water molecules to split into hydrogen gas (H2) and hydroxide ions (OH-).

2NaCl + 2H2O → 2NaOH + H2 + Cl2

The hydroxide ions then combine with the sodium ions (Na+) present in the salt water to form sodium hydroxide, or caustic soda.

Purification and Concentration

Once the caustic soda has been formed, it must be purified and concentrated before it can be used in industrial processes. This is typically done through a process called evaporation, in which the caustic soda solution is heated to remove any excess water.

Uses of Caustic Soda

Caustic soda is used in a wide range of industrial processes due to its highly reactive and corrosive nature. Some common uses of caustic soda include:

- The production of paper and textiles, where it is used to break down cellulose fibers
- The manufacturing of detergents and soaps, where it is used as a cleaning agent
- The refining of petroleum, where it is used to remove sulfur and other impurities
- The production of aluminum, where it is used to dissolve the aluminum oxide

In conclusion, caustic soda is formed through the electrolysis of salt water, and is commonly used in a variety of industrial processes due to its highly reactive and corrosive nature. The purified and concentrated form of caustic soda is essential for its use in industrial applications.