To solve this question, we need to understand the pH scale and identify which value indicates an acidic solution.
The pH scale ranges from 0 to 14 and is used to measure the acidity or basicity of a solution:
- A pH value less than 7 indicates an acidic solution.
- A pH value of 7 is neutral.
- A pH value greater than 7 indicates a basic (alkaline) solution.
Now, let's examine each of the given pH values:
- Option a: 10.0
A pH of 10.0 is greater than 7, so this is a basic solution.
- Option b: 4.5
A pH of 4.5 is less than 7, so this is an acidic solution.
- Option c: 7.0
A pH of 7.0 is neutral, neither acidic nor basic.
- Option d: 9.5
A pH of 9.5 is greater than 7, so this is a basic solution.
Among the provided options, the only pH value that is less than 7 and thus indicates an acidic solution is 4.5.
Therefore, the correct answer is:
O b. 4.5
