No, tonic water is not alkaline. It is acidic.
Tonic water typically has a pH between 2.5 and 3.5. A substance is considered acidic if its pH is less than 7, neutral at pH 7, and alkaline (or basic) if its pH is greater than 7. The acidity of tonic water is primarily due to the presence of carbonic acid (formed when carbon dioxide dissolves in water) and citric acid, which is often added as a flavor enhancer.
In comparison, regular tap water usually has a pH around 7, making tonic water significantly more acidic.
