Not sure why you got downvoted for asking a good faith question, but you’re thinking of carbonic acid, which is responsible for the fizz when the pressure lowers as you pop the top and it creates carbon dioxide.

I think carbolic acid found in soft drinks and carboxylic acids (there are many of them) are found in all sorts of things (coconuts, goat fat, fragrances, pheromones, etc) but not carbonated drinks, according to Wikipedia.

https://en.m.wikipedia.org/wiki/Carboxylic_acid