Sodium in the above reaction is produced by

Answer Details

The diagram shows the equation 2NaCl(l) → 2Na(l) + Cl₂(g) with electricity as the energy source. This is the electrolysis of molten sodium chloride to produce metallic sodium and chlorine gas.

This industrial process is known as the Downs process, named after J.C. Downs who patented the Downs cell in 1924. In the Downs cell, molten NaCl (often mixed with CaCl₂ to lower the melting point from 801°C to about 600°C) is electrolysed. At the cathode, Na⁺ ions are reduced to liquid sodium metal, while at the anode, Cl⁻ ions are oxidised to produce chlorine gas.

The Bosch process produces hydrogen gas from water gas. The Chlor-alkali process electrolyses aqueous (not molten) NaCl to give NaOH, Cl₂, and H₂. The Browning process is not a standard industrial chemistry term in this context.