Hydrochloric acid

Jump to navigation Jump to search


As aqueous solution of hydrogen chloride. Hydrochloric acid is a colorless, pungent, highly corrosive liquid, however, some acid solutions may be yellowish due to dissolved iron impurities. Concentrated, or fuming, hydrochloric acid contains 38% hydrogen chloride. A dilute solution containing 5% hydrogen chloride is commonly known as muriatic acid. Hydrochloric acid is used as an etchant for Metal plates, for processing black and white photographs and for making Glass iridescent. In industry, hydrochloric acid is used in food processing, ore reduction and metal cleaning. Some grades of hydrochloric acid may have impurities such as Sulfuric acid, Nitric acid, Sodium chloride, Iron, and Chlorine.

Synonyms and Related Terms

HCl; muriatic acid; acid of sea salt; marine acid; spirit of salt


  • Toxic by ingestion and inhalation.
  • Skin contact is corrosive.
  • ThermoFisher: SDS

Physical and Chemical Properties

Soluble in water, ethanol and benzene.

pH of concentrated solution=0.1; pH of 0.1N solution=1.1, pH of 0.01N solution=2.0

Composition HCl
CAS 7647-01-0
Melting Point -83.55 C
Density 1.19 g/ml
Molecular Weight mol. wt. = 36.46
Boiling Point 19.51 C

Resources and Citations

  • Richard S. Lewis, Hawley's Condensed Chemical Dictionary, Van Nostrand Reinhold, New York, 10th ed., 1993
  • The Merck Index, Martha Windholz (ed.), Merck Research Labs, Rahway NJ, 10th edition, 1983 Comment: entry 4821
  • Matt Roberts, Don Etherington, Bookbinding and the Conservation of Books: a Dictionary of Descriptive Terminology, U.S. Government Printing Office, Washington DC, 1982
  • Van Nostrand's Scientific Encyclopedia, Douglas M. Considine (ed.), Van Nostrand Reinhold, New York, 1976
  • Random House, Webster's Encyclopedic Unabridged Dictionary of the English Language, Grammercy Book, New York, 1997
  • The American Heritage Dictionary or Encarta, via Microsoft Bookshelf 98, Microsoft Corp., 1998
  • S.R.Trotman, E.R. Trotman, Textile Analysis, J.B. Lippincott Company, Philadelphia, 1932
  • Michael McCann, Artist Beware, Watson-Guptill Publications, New York City, 1979
  • Susan E. Schur, Conservation Terminology: A review of Past & Current Nomenclature of Materials, Technology and Conservation, Spring (p.34-39); Summer (p.35-38); Fall (p.25-36), 1985
  • Photographic chemicals: www.jetcity.com/~mrjones/chemdesc.htm
  • CRC Handbook of Chemistry and Physics, Robert Weast (ed.), CRC Press, Boca Raton, Florida, v. 61, 1980 Comment: pH of concentrated solution=0.1; pH of 0.1N solution=1.1, pH of 0.01N solution=2.0