Hydrochloric Acid (Hydrogen Chloride solution, chemical formula HCl, molecular weight 36.46, CAS:7647‑01‑0, UN:1789) is a colourless transparent corrosive liquid with pungent irritating odour. It is a strong inorganic acid, miscible with water in any proportion. Widely used in metal pickling, water treatment, ore processing, food processing, chemical synthesis, dye industry and fertilizer manufacturing industries.