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Ammonia solution, also known as ammonia water, ammonium hydroxide, ammoniacal liquor, ammonia liquor, aqua ammonia, aqueous ammonia, or (inaccurately) ammonia, is a solution of ammonia in water. It can be denoted by the symbols NH 3 (aq). Although the name ammonium hydroxide suggests a salt with the composition [NH + 4][OH −
Most ammonium salts are soluble and act as acids in liquid ammonia solutions. The solubility of halide salts increases from fluoride to iodide. A saturated solution of ammonium nitrate (Divers' solution, named after Edward Divers) contains 0.83 mol solute per mole of ammonia and has a vapour pressure of less than 1 bar even at 25 °C (77 °F).
The tables below provides information on the variation of solubility of different substances (mostly inorganic compounds) in water with temperature, at one atmosphere pressure. Units of solubility are given in grams of substance per 100 millilitres of water (g/100 ml), unless shown otherwise. The substances are listed in alphabetical order.
The following chart shows the solubility of various ionic compounds in water at 1 atm pressure and room temperature (approx. 25 °C, 298.15 K). "Soluble" means the ionic compound doesn't precipitate, while "slightly soluble" and "insoluble" mean that a solid will precipitate; "slightly soluble" compounds like calcium sulfate may require heat to precipitate.
Thus, the treatment of concentrated solutions of ammonium salts with a strong base gives ammonia. When ammonia is dissolved in water, a tiny amount of it converts to ammonium ions: H 2 O + NH 3 ⇌ OH − + [NH 4] + The degree to which ammonia forms the ammonium ion depends on the pH of the solution. If the pH is low, the equilibrium shifts to ...
The diffusivity of the solvated electron in liquid ammonia can be determined using potential-step chronoamperometry. [6] Solvated electrons in ammonia are the anions of salts called electrides. Na + 6 NH 3 → [Na(NH 3) 6] + + e −. The reaction is reversible: evaporation of the ammonia solution produces a film of metallic sodium.
The table above gives properties of the vapor–liquid equilibrium of anhydrous ammonia at various temperatures. The second column is vapor pressure in kPa. The third column is the density of the liquid phase. The fourth column is the density of the vapor.
For example, the limiting acid in liquid ammonia is the ammonium ion, NH 4 + which has a pK a value in water of 9.25. The limiting base is the amide ion, NH 2 −. NH 2 − is a stronger base than the hydroxide ion and so cannot exist in aqueous solution. The pK a value of ammonia is estimated to be approximately 34 (c.f. water, 14 [3] [4]).