Final answer:
The blood contains a buffering system comprised of carbonic acid and bicarbonate ion, which helps maintain stable pH levels and ensure the functionality of various biological processes.
Step-by-step explanation:
Blood is an important example of a buffered solution, with the principal acid and ion responsible for the buffering action being carbonic acid, H₂CO3, and the bicarbonate ion, HCO3-. When a hydronium ion is introduced to the blood stream, it is removed primarily by the reaction:
H3O+ (aq) + HCO3- (aq) → H₂CO3(aq) + H₂O(1)
An added hydroxide ion is removed by the reaction:
OH(aq) + H₂CO3(aq)
An important buffer in the blood is a mixture of carbonic acid (H₂CO₃) and bicarbonate ion (HCO₃⁻). This buffer system effectively maintains the pH of blood. When the blood becomes too acidic, the bicarbonate ion can absorb excess hydrogen ions, converting them into carbonic acid, thus stabilizing pH levels. Conversely, when the blood is too basic, carbonic acid can donate hydrogen ions, neutralizing excess hydroxide ions. This system efficiently minimizes changes in the pH of the blood, essential for maintaining homeostasis in the human body.