AFOQT Practice Test

What pH level indicates a strong base?

1. A pH of 4

2. A pH of 6

3. A pH of 8

4. A pH between 7 and 14

The correct answer is: A pH between 7 and 14

A strong base is one that is capable of completely dissociating in water, resulting in a high concentration of hydroxide ions (OH⁻) and a corresponding pH level typically above 7. The pH scale ranges from 0 to 14, where a pH of 7 is considered neutral. Therefore, any pH level above 7 indicates a basic or alkaline solution, with higher values representing stronger bases. Specifically, a pH that is significantly greater than 7, approaching 14, suggests a very strong base. Hence, the correct answer is that a pH level between 7 and 14 indicates a strong base. Other values provided in the options, such as pH levels of 4, 6, and 8, do not accurately represent strong bases. A pH of 4 and 6 indicate acidic and mildly acidic solutions, respectively, while a pH of 8 suggests a weak base, as it is only slightly above neutral. This understanding of the pH scale is essential for recognizing the nature of various solutions in chemistry.