Effervescence
The rapid escape of gas bubbles from a liquid during a chemical reaction.
Unit
Dimensionless
In depth
Effervescence indicates that a gaseous product is being formed faster than it can dissolve. Because the gas escapes, it removes product from the system and drives the reaction to completion. Identifying the gas by its smell or by a confirmatory test is a standard qualitative technique.
Examples in the real world
Carbonates fizzing with acid to release CO₂ that turns limewater milky; metals fizzing with acid to give hydrogen.