The "2" in the chemical formula 2NaHCO₃ means that there are two molecules of sodium bicarbonate (NaHCO₃).

Here's a breakdown:

* NaHCO₃: This represents one molecule of sodium bicarbonate, which contains one sodium atom (Na), one hydrogen atom (H), one carbon atom (C), and three oxygen atoms (O).

* 2: This coefficient indicates that there are two of these NaHCO₃ molecules present.

So, the entire formula 2NaHCO₃ represents a total of:

* 2 Sodium atoms

* 2 Hydrogen atoms

* 2 Carbon atoms

* 6 Oxygen atoms