Electrochemical Processes:
Hydrogen is also manufactured industrially by electrolysis either directly as in the case of H2O, HF, and 22-25% hydrochloric
acid or chlor-alkali electrolysis (diaphragm-cell process); or indirectly in a secondary chemical reaction, as in chlor-alkali electrolysis (mercury process via sodium amalgam). With the exception of the H2O electrolysis, hydrogen is merely a welcome byproduct which helps to make the process - involving high electrical costs - more economical. However, the hydrogenproduced by electrolysis only accounts for a small percentage of the total H2 production.