Buffer

Definition

A buffer is a solution that resists significant changes in pH when small amounts of acid or base are added. It typically consists of a weak acid and its conjugate base, or a weak base and its conjugate acid.

5 Must Know Facts For Your Next Test

1. Buffers maintain pH stability by neutralizing added acids (H+ ions) or bases (OH- ions).
2. The Henderson-Hasselbalch equation, $pH = pK_a + \log \left( \frac{[A^-]}{[HA]} \right)$, is used to calculate the pH of buffer solutions.
3. Buffers are most effective when the pH is close to the $pK_a$ value of the weak acid in the solution.
4. Biological systems heavily rely on buffers; for example, human blood maintains its pH around 7.4 using bicarbonate buffering.
5. Buffer capacity depends on the concentrations of the buffering agents; higher concentrations provide greater resistance to pH change.

Review Questions

• What components make up a typical buffer solution?
• How does the Henderson-Hasselbalch equation relate to buffers?
• Why are buffers important in biological systems?

Related terms

Conjugate Acid-Base Pair: A pair consisting of an acid and its corresponding base, differing by a single proton ($H^+$).

$pK_a$: The negative logarithm of the acid dissociation constant ($K_a$), representing an acid's strength.

Buffer Capacity: The amount of acid or base a buffer can neutralize before experiencing a significant change in pH.