Here's why:

* Chemical Formula: Baking soda's chemical formula is NaHCO₃ (sodium bicarbonate).

* pH: The pH of a baking soda solution is greater than 7, indicating it is alkaline (basic).

* Reaction with Acids: Baking soda reacts with acids to produce carbon dioxide gas, water, and a salt. This reaction is the basis for its use in baking and as an antacid.

In summary, baking soda is a weak base.