Question

The role of a buffer is to ________.

1) reduce the reabsorption of hydrogen ions in the kidneys
2) limit the change in pH with changing hydrogen ion concentrations
3) reduce the secretion of hydrogen ions in the kidneys
4) reduce the secretion of bicarbonate ions in the kidneys
5) enhance the ability of an increase in hydrogen ions to increase pH

Answer 1

The role of a buffer is to limit the change in pH associated with fluctuations in hydrogen ion concentrations, such as the bicarbonate system in the human body, which is crucial for physiological pH balance.

Step-by-step explanation:

The role of a buffer is to limit the change in pH with changing hydrogen ion concentrations. Buffers work by absorbing extra hydrogen ions (H+) or hydroxide ions (OH-) to prevent increases or decreases in pH. An important example in the human body is the bicarbonate system. This system, functioning specifically in the blood plasma, includes the bicarbonate ion (HCO3-) and carbonic acid (H2CO3) as a means to maintain pH balance. The bicarbonate ion acts as a weak base, taking up hydrogen ions, while carbonic acid acts as a weak acid, reacting with hydroxide ions. This duality allows the buffer system to mitigate pH changes when excess acid (H+) or base (OH-) is introduced into the system. As a result, buffers help to maintain the acid-base homeostasis that is crucial to the physiological functioning of our bodies.