Is sparkling water acidic?
Sparkling water is slightly acidic.
Carbonated water is ordinary water pressured up to 1-2 atmospheres of carbon dioxide gas. The gas is dissolved in the water, where its function as an acidic oxide is apparent:
The equilibrium lies strongly to the left, but it still operates.
Note that most of the things that we eat or drink that taste good, for example wine, cheese, beer, butter, egg yolks, are all slightly acidic. Carbonated water falls under this umbrella. Things that are slightly basic, egg white for example, tend to be soapy and bitter, and not flavorsome.