Effervescence in chemical reactions

Some chemical reactions result in a product that is in a different state to the reactants.

An example of this is effervescence in which a reaction in a liquid produces bubbles of gas. Effervescence is an indicator of a chemical reaction taking place.

Watch this video to see how magnesium and dilute hydrochloric acid react to produce bubbles of hydrogen gas.

The reaction of magnesium and hydrochloric acid produces effervescence