Ammonium hydroxide

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An aqueous solution of ammonia, typically containing about 28.5% ammonia by weight. Ammonium hydroxide is a colorless, alkaline liquid with a pungent ammonia odor. Household ammonia water contains about 10% ammonia by weight. Ammonium hydroxide solutions are used as cleansers and detergents to remove vegetable stains, grease, dirt, proteins, and other accretions from clothing, glass, and ceramics. It has been used in paint strippers to soften Casein paints. Ammonia water acts as a stain for wood, producing a deep red color in Mahogany. It is also used to extract color from Grass and lichens to produce a green dye.

Synonyms and Related Terms

ammonia water; ammonia solution; aqua ammonia; ammonium hydrate; 880; liquid ammonia; ammoniaque (Fr.); hydroxyde d'ammonium (Fr.)

Chemical structure

Ammonium hydroxide.jpg


Inhalation and ingestion is toxic. Contact can cause irritation and burns to skin, eyes and membranes. Will evolve ammonia gas which is toxic and slightly flammable.

Can corrode some metals.

ThermoFisher: SDS

Physical and Chemical Properties

Soluble in water. pH of concentrated solution is about 12. pKa1 = 9.25

Composition NH4OH
CAS 1336-21-6
Melting Point -77.7
Density 0.9333
Molecular Weight mol. wt.=35.05
Boiling Point -33.35

Resources and Citations

  • M.R.Gilberg, N.J.Seeley, "Liquid Ammonia as a Solvent and Reagent in Conservation" Studies in Conservation, 27:38-44, 1982.
  • R. J. Gettens, G.L. Stout, Painting Materials, A Short Encyclopaedia, Dover Publications, New York, 1966
  • G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971 Comment: p. 57
  • Richard S. Lewis, Hawley's Condensed Chemical Dictionary, Van Nostrand Reinhold, New York, 10th ed., 1993
  • Van Nostrand's Scientific Encyclopedia, Douglas M. Considine (ed.), Van Nostrand Reinhold, New York, 1976
  • The Merck Index, Martha Windholz (ed.), Merck Research Labs, Rahway NJ, 10th edition, 1983 Comment: entry 519
  • Palmy Weigle, Ancient Dyes for Modern Weavers, Watson-Guptill Publications, New York, 1974
  • 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
  • Tom Rowland, Noel Riley, A-Z Guide to Cleaning, Conserving and Repairing Antiques, Constable and Co., Ltd., London, 1981
  • Michael McCann, Artist Beware, Watson-Guptill Publications, New York City, 1979
  • John and Margaret Cannon, Dye Plants and Dyeing, Herbert Press, London, 1994
  • Book and Paper Group, Paper Conservation Catalog, AIC, 1984, 1989