Final answer:
Not all human body fluids have the same pH. Stomach acid has the lowest pH (highly acidic), followed by urine with a variable pH (acidic to alkaline), and then blood with a slightly alkaline pH.
Step-by-step explanation:
All human body fluids do not have the same pH. For instance, human blood has a slightly alkaline pH of 7.4, which is critical for the proper functioning of enzymes and is maintained by a complex buffer system within a narrow range of 7.35 to 7.45. On the other hand, stomach acid is highly acidic, with a pH of 1 to 2, which aids in food digestion and destroys harmful bacteria. The urine can have a much broader pH range, from 4.6 to 8, influenced by factors such as diet and exercise. Therefore, when ranking these body fluids from low to high pH, we get:
- Stomach acid
- Urine
- Blood
Identifying substances based on their pH, human blood (pH = 7.4) is slightly alkaline, household ammonia (pH = 11.0) is basic, and cherries (pH = 3.6) are acidic.