Difficulty: Easy

Average Score: 77%

Which of the following statements best describes the function of a buffer?

Rationale

It enables resistance to a change in pH.

Buffers function by minimizing changes in pH when acids or bases are added to a solution, thus maintaining a relatively stable pH environment. This property is crucial in various biological and chemical processes where pH fluctuations can have significant effects.

A (It permanently binds hydrogen ions.) YOUR ANSWER

Buffers do not permanently bind hydrogen ions; instead, they temporarily accept or donate hydrogen ions (H⁺) in response to changes in pH. This dynamic equilibrium allows buffers to resist pH changes without permanently altering the concentration of hydrogen ions in the solution.

B (It causes the pH of a solution to become neutral.) YOUR ANSWER

While buffers can help maintain a pH close to neutral, they do not necessarily bring the pH to exactly neutral (pH 7) in all cases. Buffers work within specific pH ranges, and their primary role is to resist changes in pH rather than forcing it to a neutral state.

C (It decreases the pH of the solution.) YOUR ANSWER

Buffers do not inherently decrease the pH of a solution; rather, they serve to stabilize it. A buffer may lower the pH if a strong base is introduced, but its main function is to moderate changes rather than to actively decrease the pH.

Conclusion

Buffers are essential in biological systems and chemical reactions because they stabilize pH levels by resisting changes despite the addition of acids or bases. The ability to absorb excess hydrogen ions or release them when needed ensures that the pH remains within a narrow range, supporting vital processes. Thus, their defining characteristic is their function in enabling resistance to pH change.

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