Hydrochloric acid is an aqueous solution of hydrogen chloride (HCl).

Wide range of industrial uses. Hydrochloric acid is a colorless and transparent liquid with a strong pungent odor and high corrosiveness. Concentrated hydrochloric acid (mass fraction is about 37) is extremely volatile, so when the container containing concentrated hydrochloric acid is opened, the hydrogen chloride gas will volatilize and combine with water vapor in the air to produce small droplets of hydrochloric acid, causing acid mist to appear above the bottle mouth. .

Industrial hydrochloric acid refers to hydrochloric acid with a concentration of 30 or 36 obtained from industrial production. Its main component is hydrogen chloride, with a chemical formula of HCl and a molecular weight of 36.46. Industrial hydrochloric acid contains impurities such as iron and chlorine, which are mixed with Fe. Slightly yellowish. Industrial hydrochloric acid is highly corrosive and can corrode metals, animal and plant fibers, and human skin. Hydrochloric acid is a colorless liquid, corrosive, and an aqueous solution of hydrogen chloride with a pungent odor. Hydrochloric acid, sulfuric acid, nitric acid, hydrobromic acid, hydroiodic acid, and perchloric acid are collectively called the six major inorganic strong acids.