Baking soda (or sodium bicarbonate, or sodium hydrogen carbonate) is a chemical compound, its formula is NaHCO3. It is a white crystalline that appears to look like a fine powder. In baking, baking soda reacts with acids such as buttermilk or yogurt to produce carbon dioxide, forcing dough to rise. Other uses for baking soda include teeth whitening, body exfoliants, treating insect bites and cleaning tough stains. It is also used in some fire extinguishers as the carbon dioxide given off helps to suffocate fires.