Hydrochloric acid, the water-based solution of hydrogen chloride gas (HCl), is a colourless inorganic chemical system with the formula H2O:HCl. Hydrochloric acid has a distinctive pungent smell. It is classified as strongly acidic that sinks and mixes with water. HCl is corrosive and non-flammable.
The main industrial applications for Hydrochloric acid include production of organic compounds (vinyl chloride for PVC), cleaning pools, purification of edible salt, neutralization and pH control as well as stimulation of oil production by injecting the liquid into the rock formation of an oil well.