The pH value of human blood is:
- A7.35 to 7.45
- B6.5 to 7.00
- C7.5 to 7.8
- D5.9 to 6.4
Show answer and explanation
Correct answer: (a) 7.35 to 7.45
Explanation
The pH of human blood is kept within a narrow range of 7.35–7.45, so blood is slightly alkaline. Buffers keep it there, mainly the carbonic acid–bicarbonate system, together with the lungs (which remove CO₂) and the kidneys (which remove acid).
A pH below 7.35 is acidosis and above 7.45 is alkalosis. Both are dangerous.