NH 4 + has the shape of a regular tetrahedron. Temperature and salinity also affect the proportion of NH 4 +. The degree to which ammonia forms the ammonium ion increases upon lowering the pH of the solution- at "physiological" pH (~7), about 99% of the ammonia molecules are protonated. Thus, the term ammonium hydroxide is a misnomer. In water, a very small percentage of NH 3 is converted into the ammonium cation (NH 4 +). This shape gives the molecule an overall dipole moment and makes it polar so that ammonia readily dissolves in water. The nitrogen atom in the molecule has a lone electron pair, and ammonia acts as a base, a proton acceptor. The ammonia molecule has a trigonal pyramid shape, as predicted by VSEPR theory. 10.4 Laboratory use of anhydrous ammonia (gas or liquid).10.3 Laboratory use of ammonia solutions.7.1 Theoretical role in alternative biochemistry.7 Ammonia's role in biologic systems and human disease.1 Structure and basic chemical properties.Household ammonia ranges in concentration from 5 to 10 weight percent ammonia. The strength of such solutions is measured in units of baume ( density), with 26 degrees baume (about 30 weight percent ammonia at 15.5 ☌) being the typical high concentration commercial product. "Household ammonia" or " ammonium hydroxide" is a solution of NH 3 in water.
Its heat of vaporization is, however, sufficiently high that NH 3 can be readily handled in ordinary beakers in a fume hood. Because NH 3 boils at -33 ☌, the liquid must be stored under pressure or at low temperature. This term emphasizes the absence of water. Although in wide use, ammonia is caustic and hazardous.Īmmonia, used commercially is usually named anhydrous ammonia. Ammonia, either directly or indirectly, is a building block for the synthesis of many pharmaceuticals. Ammonia contributes significantly to the nutritional needs of the planet as a precursor to foodstuffs and fertilizers. It is normally encountered as a gas with a characteristic pungent odor. Hydrazine Hydrazoic acid Hydroxylamine ChloramineĮxcept where noted otherwise, data are given for materials in their standard state (at 25 ☌, 100 kPa) Infobox disclaimer and referencesĪmmonia is a compound with the formula N H 3.
0 kommentar(er)
