Which phrase describes the function of a buffer?
A.
To excrete weak acids.
B.
To secrete hydrogen ions.
C.
To convert strong acids to weak acids.
D.
To convert ammonia to ammonium ions.
The correct answer and Explanation is :
The correct answer is C. To convert strong acids to weak acids.
Explanation:
A buffer is a solution that resists changes in pH when small amounts of an acid or a base are added. It works by neutralizing added acids or bases, thus maintaining a relatively stable pH. This stabilization is crucial in many biological and chemical processes where maintaining a constant pH is essential for proper function.
Buffers typically consist of a weak acid and its conjugate base, or a weak base and its conjugate acid. The weak acid can donate protons (H⁺ ions) to neutralize added bases, while the conjugate base can accept protons to neutralize added acids. This reaction helps to mitigate pH changes.
For instance, consider a buffer solution containing acetic acid (CH₃COOH) and sodium acetate (CH₃COONa). If an acid is added to the solution, the acetate ions (CH₃COO⁻) will react with the added H⁺ ions to form acetic acid, thus reducing the impact on the pH. Conversely, if a base is added, acetic acid will donate H⁺ ions to react with the hydroxide ions (OH⁻), forming water and acetate ions, again minimizing pH changes.
Buffers do not excrete acids, secrete hydrogen ions, or convert ammonia to ammonium ions. Instead, their primary function is to maintain pH stability by neutralizing additions of strong acids or bases, which helps to prevent significant changes in the pH of the solution. This ability to convert strong acids or bases into weaker forms through these reactions is what allows buffers to stabilize pH effectively.