Effervescence is the escape of gas from an
aqueous solution
An aqueous solution is a solution in which the solvent is water. It is mostly shown in chemical equations by appending (aq) to the relevant chemical formula. For example, a solution of table salt, or sodium chloride (NaCl), in water would be re ...
and the foaming or fizzing that results from that release. The word effervescence is derived from the
Latin verb ''fervere'' (to boil), preceded by the adverb ''ex''. It has the same linguistic root as the word
fermentation
Fermentation is a metabolic process that produces chemical changes in organic substrates through the action of enzymes. In biochemistry, it is narrowly defined as the extraction of energy from carbohydrates in the absence of oxygen. In food ...
.
Effervescence can also be observed when opening a bottle of champagne, beer or carbonated beverages such as some carbonated
soft drinks
A soft drink (see § Terminology for other names) is a drink that usually contains water (often carbonated), a sweetener, and a natural and/or artificial flavoring. The sweetener may be a sugar, high-fructose corn syrup, fruit juice, a s ...
. The visible bubbles are produced by the escape from solution of the dissolved gas (which itself is not visible while dissolved in the liquid).
Although CO
2 is most common for beverages,
nitrogen gas is sometimes deliberately added to certain beers. The smaller bubble size creates a smoother
beer head. Due to the poor solubility of nitrogen in beer,
kegs or
widgets are used for this.
In the laboratory, a common example of effervescence is seen if
hydrochloric acid is added to a block of
limestone. If a few pieces of
marble or an
antacid tablet are put in hydrochloric acid in a
test tube fitted with a
bung, effervescence of
carbon dioxide can be witnessed.
:
CaCO3 + 2 HCl -> CaCl2 + H2O + CO2 (^)
This process is generally represented by the following
reaction, where a pressurized dilute solution of
carbonic acid in water releases gaseous carbon dioxide at
decompression:
:
H2CO3 -> H2O + CO2 (^)
In simple terms, it is the result of the chemical reaction occurring in the liquid which produces a gaseous product.
[G. Liger-Belair ''et al.'', "Study of Effervescence in a Glass of Champagne: Frequencies of Bubble Formation, Growth Rates, and Velocities of Rising Bubbles"]
Am. J. Enol. Vitic.
50:3 (1999), 317–323.
Effervescence is also a human characteristic of expression, in tandem with ecstasy or exhuberant joy (associated with The 'fountain of youth').
See also
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Cavitation
Cavitation is a phenomenon in which the static pressure of a liquid reduces to below the liquid's vapour pressure, leading to the formation of small vapor-filled cavities in the liquid. When subjected to higher pressure, these cavities, cal ...
*
Carbonation
*
Effervescent tablet
*
Precipitation (chemistry)
In an aqueous solution, precipitation is the process of transforming a dissolved chemical substance, substance into an insoluble solid from a Supersaturated solution, super-saturated solution. The solid formed is called the precipitate. In cas ...
, the "down-arrow"
References
Chemical processes
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