included explicitly. It indicates that the substances are dissolved in water. Though all three substances, HCl, NaOH and NaCl are capable of existing as pure compounds, in aqueous solutions they are fully dissociated into the aquated ions H+, Cl−, Na+ and OH−. Example: Baking Powder When combined with water, the sodium bicarbonate and acid salts react to produce gaseous carbon dioxide. Whether commercially or domestically prepared, the principles behind baking powder formulations remain the same. The acid-base reaction can be generically represented as shown: NaHCO3 + H+ → Na+ + CO2 + H2O The real reactions are more complicated because the acids are complicated. For example, starting with baking soda and monocalcium phosphate, the reaction produces carbon dioxide by the following stoichiometry: 14 NaHCO3 + 5 Ca(H2PO4)2 → 14 CO2 + Ca5(PO4)3OH + 7 Na2HPO4 + 13 H2O A typical formulation (by weight) could call for 30% sodium bicarbonate, 5–12% monocalcium phosphate, and 21–26% sodium aluminium sulfate. Alternately, a commercial baking powder might use sodium acid pyrophosphate as one of the two acidic components instead of sodium aluminium sulfate. Another typical acid in such formulations is cream of tartar (KC4H5O6), a derivative of tartaric acid. Brønsted–Lowry definition The Brønsted–Lowry definition, formulated in 1923, independently by Johannes Nicolaus Brønsted in Denmark and Martin Lowry in England, is based upon the idea of protonation of bases through the deprotonation of acids – that is, the ability of acids to "donate" hydrogen ions (H+)—otherwise known as protons—to bases, which "accept" them."Removal and addition of a proton from the nucleus of an atom does not occur – it would require very much more energy than is involved in the dissociation of acids." An acid–base reaction is, thus, the removal of a hydrogen ion from the acid and its addition to the base. The removal of a hydrogen ion from an acid produces its conjugate base, which is the acid with a hydrogen ion removed. The reception of a proton by a base produces its conjugate acid, which is the base with a hydrogen ion added. Unlike the previous definitions, the Brønsted–Lowry definition does not refer to the formation of salt and solvent, but instead to the formation of conjugate acids and conjugate bases, produced by the transfer of a proton from the acid to the base. In this approach, acids and bases are fundamentally different in behavior from salts, which are seen as electrolytes,