To determine which number represents a basic pH, we need to understand the pH scale. The pH scale ranges from 0 to 14:
- A pH value below 7 is considered acidic.
- A pH value of exactly 7 is considered neutral.
- A pH value above 7 is considered basic.
Given the values 4 and 9:
- A pH of 4 is below 7, so it is acidic.
- A pH of 9 is above 7, so it is basic.
Therefore, the number that represents a basic pH is:
Answer for Blank 1:
9
