Effervescence

For the sociological concept, seeCollective effervescence.For the racehorse, seeEffervescing (horse).For the American rock band, seeEvanescence.For other uses of "fizz", seeFizz (disambiguation).

Bubbles of carbon dioxide float to the surface of acarbonated soft drink.

Effervescenceis the escape of gas from anaqueous solutionand the foaming or fizzing that results from that release.The word effervescence is derived from theLatinverbfervere(to boil), preceded by the adverbex.It has the same linguistic root as the wordfermentation.

Effervescence can also be observed when opening a bottle of champagne, beer or carbonated beverages such as some carbonatedsoft drinks.The visible bubbles are produced by the escape from solution of the dissolved gas (which itself is not visible while dissolved in the liquid).

In beverages

Further information:Carbonated water

Although CO₂is most common for beverages,nitrogen gasis sometimes deliberately added to certain beers. The smaller bubble size creates a smootherbeer head.Due to the poor solubility of nitrogen in beer,kegsorwidgetsare used for this.

Chemistry

Main article:Gas evolution reaction

In the laboratory, a common example of effervescence is seen ifhydrochloric acidis added to a block oflimestone.If a few pieces ofmarbleor anantacidtablet are put in hydrochloric acid in atest tubefitted with abung,effervescence ofcarbon dioxidecan be witnessed.

CaCO₃+ 2 HCl → CaCl₂+ H₂O + CO₂↑

This process is generally represented by the followingreaction,where a pressurized dilute solution ofcarbonic acidin water releases gaseous carbon dioxide atdecompression:

H₂CO₃→ H₂O + CO₂↑

In simple terms, it is the result of the chemical reaction occurring in the liquid which produces a gaseous product.

See also

• Cavitation
• Carbonation
• Effervescent tablet
• Precipitation (chemistry),the "down-arrow"