Concept:A buffer is defined by its ability to maintain a relatively stable hydrogen ion concentration upon the addition of small amounts of acid or base.
Formula:$$ \text{pH} = \text{pK}_a + \log \frac{[\text{Salt}]}{[\text{Acid}]} $$
Solution:- Buffers contain a weak acid and its conjugate base (or a weak base and its conjugate acid).
- These components neutralize small added amounts of \( \text{H}^+ \) or \( \text{OH}^- \).
- As a direct result, the pH of the solution is kept stable.
Why other options are incorrect:While resisting pH implicitly resists pOH, the standard chemical definition specifically highlights the resistance to changes in pH. \( \text{pK}_a \) and \( \text{pK}_b \) are constants that do not change regardless of the buffer action.
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