This is a process called nucleation, which is the conversion from one state (like liquid carbonic acid) to another (CO2 gas) ...
The weight of soda being accurately known which will combine with a definite weight of carbonic acid, or in other words, the equivalent proportions of their composition being well established ...
If you've ever accidentally had nothing to drink but soda water all day long ... reaction in your mouth turns carbon dioxide into carbonic acid. And acid erodes tooth enamel.
Occasionally carbonate of soda was substituted for saleratus. In this process it is the lactic acid which displaces the carbonic acid gas from the saleratus, or the carbonate of potash of chemists.
"Carbonic acid, or anything acidic ... Sparkling water comes in at around 5, and a sugary soda is highly acidic at 2.5. So, while sparkling water is not as bad for your teeth as soda, still ...