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How can electrolysis of molten sodium chloride produce chlorine and sodium metal?

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A labeled diagram of the chlorine element from the periodic table shows its atomic number 17, symbol Cl, electron configuration, and atomic weight range. The box is shaded green to indicate chlorine is a halogen, with icons for orthorhombic crystal structure, gas state at room temperature, and strong acidity. A key explains the icons and colors used. — chlorine Properties of chlorine.

The electrolysis of molten sodium chloride is a process used to produce metallic sodium and chlorine gas by passing an electric current through the substance to induce a chemical change.21

In this process, an electrolytic cell is utilized to facilitate the separation of the compound into its constituent elements. Because pure sodium chloride has a high melting point, it is typically mixed with calcium chloride to lower the temperature required for the process.23

During electrolysis:
* At the cathode (negative electrode): Sodium ions gain electrons (reduction) to form metallic sodium.2
* At the anode (positive electrode): Chloride ions lose electrons (oxidation) to form chlorine gas.2

This method, commonly performed using the Downs cell process, is a vital industrial technique because it allows for the simultaneous production of two highly useful chemical products. It is important to distinguish this from the electrolysis of an aqueous solution of sodium chloride, which instead yields sodium hydroxide and chlorine gas.312