9. Human blood, which has a pH of approximately 7.4, is a/an _______ substance.
To determine whether human blood, with a pH of approximately 7.4, is an acidic, basic, or neutral substance, we need to understand the concept of pH.
The pH scale measures the acidity or alkalinity (basicity) of a substance. It ranges from 0 to 14, where pH 7 is considered neutral. A pH below 7 indicates acidity, while a pH above 7 indicates alkalinity (basicity).
In this case, human blood has a pH of approximately 7.4. Since 7.4 is greater than 7 (neutral), human blood is slightly alkaline or basic. Therefore, the answer to your question is that human blood is a basic substance.