noun
also sodium acid carbonate
: a crystalline salt NaHCO 3 that is less soluble in water than normal sodium carbonate and gives a weakly alkaline reaction, that evolves carbon dioxide when heated, that is found in nature and is also made by passing carbon dioxide into a solution of the normal carbonate or by purifying the intermediate product of the Solvay process, that is used chiefly in baking powders, in carbonated beverages and effervescent salts, in fire extinguishers, and in medicine as an antacid, and that with carbonic acid constitutes the principal inorganic buffer system of blood and other body fluids; sodium hydrogen carbonate — called also baking soda, nahcolite, soda