Final answer:
The concentration of hydrogen ions (m[H+]) in human blood with an average pH of 7.4 is approximately 4.00×10^-8, which closely corresponds to option b.
Step-by-step explanation:
The question relates to finding the concentration of hydrogen ions (m[H+]) in human blood based on its pH level, which ranges from 7.35 to 7.45. The formula to convert pH to m[H+] is given by m[H+] = 10^-pH. Using the average pH of 7.4, this would be m[H+] = 10^-7.4, which calculates to approximately 3.98×10-8. This value is closest to option b, which is 4.00×10-8. It is important to note that the pH of human blood is maintained within a narrow range due to the presence of buffers, which are part of the body's homeostatic mechanisms to prevent life-threatening disorders.