Hydrochloric acid

From GAWDAwiki

Hydrochloric acid is a solution of hydrogen chloride in water. Hydrogen chloride occurs as either a colourless liquid with a an irritating, pungent odour, or a colourless to slightly yellow gas which can be shipped as a liquefied compressed gas; highly soluble in water.

Chemical properties

Hydrochloric acid is one of the most corrosive of the non-oxidising acids in contact with copper alloys, and is handled in dilute solutions. Contact with metals produces hydrogen gas, which creates the chance of an explosion. It produces poisonous gas, including chlorine, in a fire. It is soluble in benzene, alcohol, and ether; it is insoluble in hydrocarbons, and incompatible or reactive with metals, hydroxides, amines, and alkalis. Hydrochloric acid's fumes have an acid, penetrating odour. Aqueous solutions of hydrochloric acid attack and corrode nearly all metals, except mercury, silver, gold, platinum, tantalum, and certain alloys. It may be coloured yellow by traces of iron, chlorine, and organic matter. Non-flammable gas.

Common uses

It is used in the manufacture of phosphoric acid, chlorine dioxide, ammonium chloride, fertilisers, dyes, and artificial silk and pigments for paints. It is used as a refining ore in the production of tin and tantalum, as a lab reagent, and as a metal treating agent. It is used to remove scale and dust from boilers and heat exchange equipment, to clean membranes in desalination plants, to increase oil well output, to prepare synthetic rubber products by treating isoprene, and to clean and prepare other metals for coatings. It is used in the neutralisation of waste streams, the recovery of zinc from galvanised iron scrap, the production of chloride chemicals, the production of vinyl chloride from acetylene and alkyl chlorides from olefins, the manufacture of sodium glutamate and gelatine, the conversion of cornstarch to syrup, sugar refining, electroplating, soap refining, leather tanning, and the photographic, textile, brewing, and rubber industries. It is used to maintain pH balance in swimming pools, spas, etc. It is also used as a bactericide, a fungicide, and a virucide to disinfect bathrooms, kitchens and food preparation areas, and other areas in commercial and industrial buildings, in hospitals, in nursing homes, and in and around household dwellings. It is used in food processing as a starch modifier.^[1]