Hydrogenklorid

Hydrogenklorid, or hydrogen chloride, is a diatomic molecule with chemical formula HCl. It is a colorless gas at room temperature with a pungent, acrid odor. In water, it forms hydrochloric acid, a strong mineral acid widely used in industry and chemistry. Hydrogen chloride is highly soluble in water; the aqueous solution dissociates completely into hydronium and chloride ions, giving a low pH.

Industrial production of hydrogen chloride is mainly by direct synthesis from hydrogen and chlorine: H2 + Cl2 → 2 HCl. It can also be recovered from chlorine-containing process streams and during the manufacture of chlorinated organics. Pure HCl gas is often dissolved in water to prepare hydrochloric acid.

Applications include the use of hydrochloric acid for metal pickling, ore refining, pH control in chemical processing, and the production of chlorides and organic intermediates, including vinyl chloride monomer for polyvinyl chloride. Hydrogen chloride gas is used in certain chemical syntheses and in gas-cleaning applications.

Safety and handling considerations: Hydrogen chloride is highly corrosive to skin, eyes and mucous membranes and is a strong respiratory irritant. It reacts with water to form hydrochloric acid, so exposure to moist air can lead to corrosion of materials and health hazards. It reacts with many metals, releasing hydrogen gas. Use in well-ventilated areas, with appropriate personal protective equipment; store in corrosion-resistant containers away from moisture and bases.

Storage: Stored as a compressed gas in suitable materials, or as concentrated aqueous solutions. Containers should be kept tightly closed and away from moisture.