Final answer:
Buffers help prevent drastic changes in pH by absorbing excess H+ or OH- ions. They do this by reacting with these ions to buffer changes in acidity or alkalinity, illustrated by systems such as the human body's bicarbonate buffer system. Therefore, correct option is a.
Step-by-step explanation:
To discuss how buffers help prevent drastic swings in pH, it is important to understand that buffers are solutions that can absorb excess hydrogen ions (H+) or hydroxide ions (OH-). This ability allows buffers to prevent significant changes in the pH levels of a solution.
Buffers operate by either taking up excess H+ or OH- ions, depending on which is present. For example, in the bicarbonate system in the human body's blood, the buffer maintains pH by converting bicarbonate ions and free hydrogen ions into carbonic acid when pH starts to rise, thereby absorbing excess H+ and preventing an increase in acidity.
Similarly, if the pH starts to drop, indicating increased alkalinity, the buffer can release H+ ions to normalize it.
Key Takeaway
A buffer is a solution that resists sudden changes in pH, either by absorbing excess H+ ions to prevent increases in acidity or by releasing them to prevent decreases in acidity.