When combined with the element sodium, hydrogen carbonate produces sodium hydrogen carbonate, or baking soda; and bicarbonate of soda, a crystalline white soluble compound. According to the website General Chemistry, baking soda is used as an antacid for acid indigestion and heartburn. It can also be used to absorb odors, hence its use in a box in the refrigerator to counteract food smells. Baking soda also has cleaning properties, and is used as an ingredient in toothpaste or independently as a cleaning substance.
Hydrogen carbonate, or bicarbonate as it is referred to by WebMD, is of great value as a testing marker for certain conditions and diseases. If the level is high, then that could be an indication of chronic obstructive pulmonary disease, heart disease or dehydration, among other conditions cited by WebMD. A low level of bicarbonate could be a predictor of liver or kidney disease, diabetes or other conditions.
Sodium hydrogen carbonate is the main ingredient in baking powder, a substance that differs from baking soda in that anti-caking agents, such as starches, are added to the sodium hydrogen carbonate, according to the website Science is Fun. These additions produce a powder that releases carbon dioxide gas, giving baking powder the characteristics desired to cause the leavening, or rising, effect in breads and cakes.