Chemistry
Advanced

Henderson–Hasselbalch

pH of a buffer solution.

Formula

pH=pKa+log⁡[A−][HA]pH = pK_a + \log\frac{[A^-]}{[HA]}

Variables

pK_aAcid dissociation
[A^-]Conjugate base
[HA]Acid

Example

A buffer with equal [A⁻] and [HA] has pH = pKₐ (the log term is zero).

Did You Know?

The Henderson–Hasselbalch equation is how your blood keeps its pH nearly constant to keep you alive.

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