Hypothetically speaking, if sodium carbonate is the result of baking, I would assume that proton from sodium bicarb is lost due to the combustion like reaction from releasing CO2 and H2O.
Hence, Carbonate (Na2CO3) has a high alkalinity effect when dosed.
It can accept 2 protons relative to bicarbonate?s (NAHCO3) capability of accepting only 1.
Not really sure which is which, but a 1:1 ratio is most likely evident with sodium carbonate (Na2CO3) and calcium chloride (CaCl2), a 1:1 equivalent if considering the exchange of sodium and chloride ions.
However, with brands such as ESV's B-ionic, there is mixture of both alkalinity components of carb and bicarb.