Why bubbles are produced when acetic acid is added to a solution of sodium hydrogen carbonate?

When acetic acid (CH3COOH) is added to a solution of sodium hydrogen carbonate (NaHCO3), a chemical reaction occurs. This reaction is an example of an acid-base reaction, because acetic acid is a weak acid and sodium hydrogen carbonate is a weak base.

The chemical equation for this reaction is:

CH3COOH + NaHCO3 → CH3COONa + H2O + CO2

In this reaction, acetic acid reacts with sodium hydrogen carbonate to form sodium acetate (CH3COONa), water (H2O), and carbon dioxide (CO2).

The bubbles you see are the carbon dioxide gas being released. This happens because when an acid reacts with a carbonate or a bicarbonate, carbon dioxide is produced and released into the atmosphere.

So, the bubbles are a visual sign of the chemical reaction taking place and the creation of a new product, carbon dioxide.