Final answer:
The sour taste of tonic water indicates that it is acidic; therefore, the pH of tonic water is less than 7, making it acidic.
Step-by-step explanation:
The sour taste of tonic water hints at its pH level. Sour taste is a characteristic of acidic substances. Since tonic water has a slightly sour taste, this indicates that the pH of tonic water is acidic, which means option 2) The pH is acidic, is the correct answer. Water has a pH of 7 and is considered neutral. Anything with a pH lower than 7 is acidic, while a pH higher than 7 is basic. Since tonic water tastes sour, it is similar to other acidic substances, such as vinegar, and therefore has a pH that is less than 7.
Tonic water has a slightly sour taste, which suggests that it has an acidic pH. Acids have a pH lower than 7.0, while neutral substances have a pH of 7.0. Therefore, the hint of a sour taste in tonic water indicates that its pH is acidic.