In general chemistry, what is the primary function of a buffer solution?

• A. To completely neutralize any added acid or base so the pH becomes exactly 7
• B. To increase the rate of reaction by acting as a catalyst
• C. To change the pH rapidly when a small amount of acid or base is added
• D. To resist changes in pH when small amounts of acid or base are added

Answer: (D)

Verified step by step guidance

1. Understand that a buffer solution is designed to maintain the pH of a solution within a narrow range, even when small amounts of acid or base are added.
2. Recognize that buffers consist of a weak acid and its conjugate base (or a weak base and its conjugate acid), which work together to neutralize added H\_3O\^+ or OH\^- ions.
3. Recall the general buffer action: when an acid (H\_3O\^+) is added, the conjugate base component of the buffer reacts with it to minimize pH change; when a base (OH\^-) is added, the weak acid component donates H\_3O\^+ to neutralize it.
4. Note that buffers do not completely neutralize all added acid or base to reach a pH of exactly 7, but rather resist changes in pH, keeping it relatively stable.
5. Conclude that the primary function of a buffer solution is to resist changes in pH when small amounts of acid or base are added, maintaining the solution's pH within a desired range.