When you open a bottle of a soft drink and leave it open, the drink eventually goes flat. This happens because the equilibrium between carbonic acid and carbon dioxide shifts to produce

Question

Quizplus · Accepted Answer

When a soft drink is opened, the carbon dioxide gas escapes from the liquid and goes into the air, which lowers the concentration of carbon dioxide in the drink. In order to reach a new equilibrium, some of the carbonic acid dissociates to produce more carbon dioxide, which creates the bubbly sensation in carbonated drinks. Therefore, leaving the drink open will shift the equilibrium towards producing more carbon dioxide, making the drink go flat.

When You Open a Bottle of a Soft Drink and Leave