Final answer:
A substance with a pH of 6 is classified as an acid, based on the pH scale which measures the amount of hydrogen ions present in a substance. A pH below 7 indicates acidity, and since 6 is less than 7, it's considered acidic.
Step-by-step explanation:
A substance with a pH of 6 would be classified as an acid. The pH scale, which ranges from 0 to 14, measures the amount of hydrogen ions (H+) in a substance. A pH level below 7 is considered acidic, with lower pH values indicating stronger acidity. For example, hydrochloric acid and lemon juice are both very acidic substances. Conversely, with a pH above 7, a substance is basic (alkaline), where higher values represent stronger basicity, such as sodium hydroxide and many household cleaners. Since a pH of 6 is less than 7, it indicates the presence of more hydrogen ions than hydroxide ions (OH), qualifying the substance as an acid, albeit a weak one.
Exercise 7.6.1 further provides examples of pH levels to identify substances as acidic, basic, or neutral:
- Human blood with pH = 7.4 is slightly basic (alkaline).
- Household ammonia with pH = 11.0 is a base.
- Cherries with pH = 3.6 are acidic.