Acid salt
1740813
215681677
2008-05-29T06:40:47Z
LOL
162210
neutrallized→neutralized
[[Image:SodiumBicarbonate.png|thumb|right|Chemical structure of [[sodium bicarbonate]]]]
'''Acid salts''' are a class of [[salt (chemistry)|salts]] formed when a dibasic or tribasic [[acid]] has been [[neutralization|neutralized]] to some degree. Because the acid is only partially neutralized, one or more replaceable [[proton]]s remain. Typically this will lead to a formula with one or more metal ions, one or more protons, and an anion, such as [[sodium bicarbonate]] (NaHCO<sub>3</sub>), [[sodium hydrosulfide]] (NaHS), [[sodium bisulfate]] (NaHSO<sub>4</sub>), [[monosodium phosphate]] (NaH<sub>2</sub>PO<sub>4</sub>), and [[disodium phosphate]] (Na<sub>2</sub>HPO<sub>4</sub>).
For example, in preparing [[sodium sulfate]] (Na<sub>2</sub>SO<sub>4</sub>) a certain amount of [[sodium hydroxide]] (NaOH) is needed to neutralize the [[sulfuric acid]] (H<sub>2</sub>SO<sub>4</sub>) to produce this salt. When preparing [[sodium bisulfate]] (NaHSO<sub>4</sub>), half of the required amount of sodium hydroxide for neutralization is used.
Such compounds can act either as an acid or a [[base (chemistry)|base]]: addition of an acid will restore protons, and addition of a base will consume protons. The actual [[pH]] of a solution of an acid salt will depend on the equilibrium constants involved, and whether the anion is a better proton donor or proton acceptor. A comparison between the ''K''<sub>b</sub> and ''K''<sub>a</sub> will indicate this: if ''K''<sub>b</sub> > ''K''<sub>a</sub>, the solution will be basic, whereas if ''K''<sub>b</sub> < ''K''<sub>a</sub>, the solution will be acidic.
==Use in food==
{{main|baking powder}}
Some acid salts are used in baking. They are found in baking powders and are typically divided into low-temperature (or single-acting) and high-temperature (or double-acting) acid salts. Common low-temperature acid salts react at room temperature to produce a leavening effect. They include [[cream of tartar]], [[calcium phosphate]], and [[citrate]]s. High-temperature acid salts produce a leavening effect during baking and are usually [[aluminium]] salts such as [[calcium aluminium phosphate]]. Some acid salts may also be found in [[non-dairy creamer|non-dairy coffee creamers]].
==See also==
* [[alkali salt]]
==References==
{{Unreferenced|date=February 2008}}
{{reflist}}
[[Category:salts]]
[[es:Sal ácida]]
[[pt:Sal ácido]]
[[zh:酸式盐]]