Equation for the Decomposition of Sodium Bicarbonate (Baking Soda)

The decomposition reaction of sodium bicarbonate or baking soda is an important chemical reaction for baking because it helps baked goods rise. It's also how you can make sodium carbonate, another useful chemical, also called washing soda.

The Balanced Equation

The balanced equation for the decomposition of sodium bicarbonate into sodium carbonate, carbon dioxide, and water is:

2 NaHCO3(s) → Na2CO3(s) + CO2(g) + H2O(g)

Like most chemical reactions, the rate of the reaction depends on temperature. When dry, baking soda doesn't decompose very quickly, although it does have a shelf life, so you should test it before using it as a cooking ingredient or in an experiment.

One way to speed up the decomposition of the dry ingredient is by heating it in a warm oven. Baking soda starts to break into washing soda, carbon dioxide, and water at room temperature when mixed with water, which is why you shouldn't store baking soda in an open container or wait too long between mixing a recipe and putting it in the oven. As the temperature increases to the boiling point of water (100 Celcius), the reaction goes to completion, with the decomposition of all the sodium bicarbonate.

Sodium carbonate or washing soda also undergoes a decomposition reaction, although this molecule is more heat-stable than sodium bicarbonate. The balanced equation for the reaction is:

Na2CO3(s) → Na2O(s) + CO2(g)

The decomposition of anhydrous sodium carbonate into sodium oxide and carbon dioxide occurs slowly at room temperature and proceeds to completion at 851 C (1124 K).