Sodium bicarbonate (baking soda) is a salt that has acid-neutralizing properties and releases carbon dioxide gas when combined with acid. It is used, among other things, as a leavening agent for gingerbread and beaver doughs during the pre-Christmas season. When heated, baking soda (NaHCO3) decomposes into soda (Na2CO3), carbon dioxide (CO2), and water (H2O), which creates the important leavening effect for baking.