Sodium bicarbonate is used in food as a leavening agent and in effervescent powders. These are a mixture of baking soda with a solid acid such as citric acid. But it is also found in bath tablets and fire extinguisher powders. It is also used to soften water.
 Sodium carbonates include soda (sodium carbonate, disodium carbonate), baking soda (sodium bicarbonate, sodium hydrogen carbonate) and sodium sesquicarbonate, which is a mixed crystal of soda and baking soda. While soda is mainly used to regulate the acidity of drinking water and to dissolve cocoa and milk protein, baking soda is mainly used in baking powder. Sodium carbonates are broken down by contact with acids. This releases carbon dioxide. This increases the volume of dough, for example - it rises and becomes fluffy.