Hydrogen Chloride is used to produce hydrochloric acid, which is a key compound in the following industries: chlor-alkali, vinyl chloride monomer for PVC plastics, pulp & paper, epichlorohydrin, etc… and has smaller scale applications in metallurgical processes, gelatine and food products, etc.
Hydrogen Chloride is economically and reliably produced by burning chlorine with hydrogen, this is why HCl synthesis plants are commonly called chlorine burners.