Baking Soda Chemical Formula (Sodium Bicarbonate)

Molecular Formula for Baking Soda or Sodium Bicarbonate

This is the chemical formula of baking soda, showing its ions in water.
This is the chemical formula of baking soda, showing its ions in water. Anne Helmenstine
by Anne Marie Helmenstine, Ph.D.
Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels.
Updated March 08, 2019

Baking soda is the common name for the chemical sodium bicarbonate or sodium hydrogen carbonate. The molecular formula of sodium bicarbonate is NaHCO3. The compound is a salt that dissociates into sodium (Na+) cation and carbonate (CO3-) anions in water. Baking soda is an alkaline white crystalline solid, usually sold as a powder. It has a slightly salty flavor.

Decomposition Into Sodium Carbonate

At temperature higher than 50 °C (122 °F), baking soda decomposes into washing soda or sodium carbonate, along with water and carbon dioxide. The speed of the decomposition depends on temperature and proceeds rapidly at ordinary baking temperatures. The dehydration reaction is:

2 NaHCO3 → Na2CO3 + H2O + CO2

At still higher temperatures (over  850 °C or 1560 °F), the carbonate becomes the oxide. The reaction is:

Na2CO3 → Na2O + CO2

This reaction is used in dry powder fire extinguishers based on baking soda. The carbon dioxide helps to suffocate the flame.

History

French chemist Nicolas Leblanc produced sodium carbonate or soda ash in 1791. In the early 1800s, fishermen used sodium bicarbonate or potassium bicarbonate (collectively called saleratus) to preserve fresh fish. In 1846, American bakers Austin Church and John Dwight built the first factory in the United States that made baking soda from sodium carbonate and carbon dioxide.