3D model (JSmol)
|E number||E527 (acidity regulators, ...)|
|NH4OH or NH5O|
|Molar mass||35.04 g/mol|
|Odor||"Fishy", highly pungent|
|Density||0.91 g/cm3 (25% w/w)
0.88 g/cm3 (35% w/w)
|Melting point||−57.5 °C (−71.5 °F; 215.7 K) (25% w/w)
−91.5 °C (35% w/w)
|Boiling point||37.7 °C (99.9 °F; 310.8 K) (25% w/w)|
Std enthalpy of
|R-phrases (outdated)||R34, R50|
|S-phrases (outdated)||(S1/2), S26, S36/37/39, S45, S61|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
|what is ?)(|
Ammonia solution, also known as ammonia water, ammonical liquor, ammonia liquor, aqua ammonia, aqueous ammonia, or (inaccurately) ammonia, is a solution of ammonia in water. It can be denoted by the symbols NH3(aq). It is sometimes thought of as a solution of ammonium hydroxide. Although the name ammonium hydroxide suggests an alkali with composition [NH4+][OH−], it is actually impossible to isolate samples of NH4OH. The ions NH4+ and OH− do not account for a significant fraction of the total amount of ammonia except in extremely dilute solutions.
- 1 Basicity of ammonia in water
- 2 Saturated solutions
- 3 Applications
- 4 Laboratory use
- 5 See also
- 6 References
- 7 Further reading
- 8 External links
Basicity of ammonia in water
- NH3 + H2O ⇌ NH4+ + OH−.
- Kb = [NH4+][OH−]/[NH3] = 1.8×10−5
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Like other gases, ammonia exhibits decreasing solubility in solvent liquids as the temperature of the solvent increases. Ammonia solutions decrease in density as the concentration of dissolved ammonia increases. At 15.6 °C (60.1 °F), the density of a saturated solution is 0.88 g/ml and contains 35% ammonia by mass, 308 g/l w/v, (308 grams of ammonia per litre of solution) and has a molarity of approximately 18 mol L−1. At higher temperatures, the molarity of the saturated solution decreases and the density increases.
When solutions that are saturated at cold temperatures are sealed in containers and subsequently warmed, the vapor pressure of ammonia gas increases. Unsealing such containers can lead to a burst of ammonia gas. In extreme cases, the containers could rupture.
From a chemist's perspective, one should be aware that the concentration of a near-saturated solution in an open container drops continually as the container is handled in a warmer environment. Thus, old samples of ammonia solution will deviate from 18 M, as can be verified by titration.
Household ammonia is dilute ammonia, which is also an ingredient of numerous other cleaning agents, including many window cleaning formulas. In addition to use as an ingredient in cleansers with other cleansing ingredients, ammonia in water is also sold as a cleaning agent by itself, usually labeled as simply "ammonia". It may be sold plain, lemon-scented (and typically colored yellow), or pine-scented (green). Commonly available ammonia with soap added is known as "cloudy ammonia".
In industry, aqueous ammonia can be used as a precursor to some alkyl amines, although anhydrous ammonia is usually preferred. Hexamethylenetetramine forms readily from aqueous ammonia and formaldehyde. Ethylenediamine forms from 1,2-dichloroethane and aqueous ammonia.
In furniture-making, ammonia solution was traditionally used to darken or stain wood containing tannic acid. After being sealed inside a container with the wood, fumes from the solution react with the tannic acid and iron salts naturally found in wood, creating a rich, dark stained look to the wood. This was commonly used during the arts and crafts movement in furniture- a furniture style which was primarily constructed of oak and stained using these methods.
Ammonia is used as a leavening agent or acidity regulator and is classified by the Food and Drug Administration as generally recognized as safe (GRAS). Its pH control abilities make it an effective antimicrobial agent.
According to Phillip Morris USA, quantities of up to 0.3% ammonium hydroxide are used in tobacco for flavor enhancement and as a processing aid. 
Treatment of straw for cattle
Aqueous ammonia is used in traditional qualitative inorganic analysis as a complexant and base. Like many amines, it gives a deep blue coloration with copper(II) solutions. Ammonia solution can dissolve silver oxide residues, such as that formed from Tollens' reagent. It is often found in solutions used to clean gold, silver, and platinum jewelry, but may have negative effects on porous gem stones like opals and pearls.
When ammonia solution is mixed with dilute hydrogen peroxide in the presence of a metal ion, such as Cu2+, the peroxide will undergo rapid decomposition.
- Record of Ammonia solution in the GESTIS Substance Database of the Institute for Occupational Safety and Health
- Zumdahl, Steven S. (2009). Chemical Principles 6th Ed. Houghton Mifflin Company. p. A22. ISBN 0-618-94690-X.
- C&L Inventory
- Housecroft, C. E.; Sharpe, A. G. (2004). Inorganic Chemistry (2nd ed.). Prentice Hall. p. 187. ISBN 978-0130399137.
- Eller, Karsten; Henkes, Erhard; Rossbacher, Roland; Höke, Hartmut (2000). "Amines, Aliphatic". Ullmann's Encyclopedia of Industrial Chemistry. doi:10.1002/14356007.a02_001. ISBN 978-3-527-30673-2.
- Rigers, Shayne; Umney, Nick. "Acidic and alkaline stains". Wood Coatings: Theory and Practice. Amsterdam: Elsevier. pp. 618–9. ISBN 978-0-444-52840-7.
- Database of Select Committee on GRAS Substances (SCOGS) Reviews: Ammonium hydroxide, U.S. Food and Drug Administration
- The Jeweler's Bench. 2015. Fine Jewelry Cleaner. Littleton, CO.
- Geornaras, I.; Sofos, J. N. (2005). "Combining physical and chemical decontamination interventions for meat". In Sofos, John Nikolaos. Improving the safety of fresh meat. Boca Raton: CRC Press. pp. 433–60. ISBN 978-0-8493-3427-6.
- Skandamis, Panagiotis N.; Nychas, George-John E.; Sofos, John N. (2010). "Meat Decontamination". In Toldrá, Fidel. Handbook of Meat Processing. Ames: Iowa State University Press. pp. 43–85. doi:10.1002/9780813820897.ch3. ISBN 978-0-8138-2089-7.
- Edwards, Jessica Renee; Fung, Daniel Y.C. (2006). "Prevention and Decontamination of Escherichia Coli O157:h7 on Raw Beef Carcasses in Commercial Beef Abattoirs". Journal of Rapid Methods and Automation in Microbiology. 14 (1): 1–95. doi:10.1111/j.1745-4581.2006.00037.x.
- External Material Safety Data Sheet – for ammonium hydroxide (10%-35% solution).