Electrolysis is a key industrial process used primarily for the extraction and purification of metals, as well as for the production of various chemicals.

At its core, electrolysis involves the passage of an electric current through a substance, leading to a chemical change. This process often results in the decomposition of the substance, which is especially beneficial for metal extraction and purification. For example, aluminium is extracted from its ore, bauxite, through electrolysis. Initially, the ore is processed to yield aluminium oxide, which is then dissolved in molten cryolite. When an electric current is applied to this mixture, aluminium is generated at the cathode.

Similarly, electrolysis is employed to purify copper. In this case, impure copper is used as the anode, while a thin sheet of pure copper acts as the cathode. As the electric current flows through the solution, copper ions are discharged at the cathode, resulting in the deposition of pure copper. Meanwhile, impurities either settle as sludge or remain dissolved in the solution.

Beyond metal extraction and purification, electrolysis is instrumental in the large-scale production of chemicals. A notable example is the electrolysis of brine, which is a sodium chloride solution. This process yields chlorine gas at the anode, while hydrogen gas and sodium hydroxide (commonly known as caustic soda) are produced at the cathode.

Moreover, electrolysis plays an important role in the electroplating industry, where it is used to coat objects with a thin layer of metal. This coating serves various purposes, including preventing corrosion, reducing friction, enhancing paint adhesion, modifying conductivity, and providing aesthetic appeal.

In summary, electrolysis is a versatile and essential process that significantly contributes to numerous industrial applications, ranging from metal extraction and purification to chemical production and electroplating.