31. The buffer action of blood is due to the presence of A.HCI and NaCI B.CI– and [CO3]2– C.CI– and [HCO3]– D.[HCO3]– and H2CO3
Answer: Option D Solution: Human blood contains a buffer of carbonic acid (H2CO3) and bicarbonate anion (HCO3-) in order to maintain blood pH between 7.35 and 7.45, as a value higher than 7.8 or lower than 6.8 can lead to death. In this buffer, hydronium and bicarbonate anion are in equilibrium with carbonic acid. Furthermore, the carbonic acid in the first equilibrium can decompose into CO2 gas and water, resulting in a second equilibrium system between carbonic acid and water. Because CO2 is an important component of the blood buffer, its regulation in the body, as well as that of O2 , is extremely important. The effect of this can be important when the human body is subjected to strenuous conditions.
