Baking soda, also known as sodium bicarbonate, has the chemical formula NaHCO3. Cream of tartar, also known as tartrate salt, has the formula KHC4H4O6. The reaction is: NaHCO3 + KHC4H4O6 ----> KNaC4H4O6 + H2O + CO2 http://home.howstuffworks.com/question57.htm