Effervescence

Effervescence is the release of gas from a mixture where water dissolves another substance, and the foaming and fizzing that results from the release.

The most common gas that is released in effervescence is carbon dioxide, however nitrogen gas can be dissolved to produce smaller bubbles.

Effervescence can be seen when opening a bottle of champagne, beer or some soft drinks. The bubbles that can be seen are produced by the escape from the dissolved gas (which cannot be seen while dissolved in the liquid).

In the laboratory, a common example of effervescence is seen when 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 cork, it is possible to see an effervescence of carbon dioxide.