Baking soda, or sodium bicarbonate, is an extremely alkaline, white, water-soluble powder. When mixed with an acid, it spurs a chemical reaction that produces carbon dioxide gas—or put more simply, it creates bubbles that cause baked goods to rise. Baking soda is a common ingredient in baked goods, such as cookies, cakes and quick breads. This product comes in a resealable bag to insure continued freshness.