A gas evolution reaction is a chemical reaction in which one of the end products is a gas such as oxygen or carbon dioxide. Gas evolution reactions may be carried out in a fume chamber when the gases produced are poisonous when inhaled or explosive.
Examples
A replacement reaction concerning zinc metal and dilute sulfuric acid.
<chem>Zn + H_2SO_4 (dil) -> ZnSO_4 + H_2 ^</chem>
In this example, diatomic hydrogen gas is released. Dilute hydrochloric acid can be used in place of dilute sulfuric acid.