Henderson-Hasselbalch Equation
| Formula / Notation | pH = pKa + log([A⁻]/[HA]) |
|---|---|
| Also Known As | Henderson-Hasselbalch equation, buffer equation, H-H equation |
What is Henderson-Hasselbalch Equation?
An equation relating the pH of a buffer solution to the pKa of the weak acid and the ratio of concentrations of the conjugate base to the weak acid: pH = pKa + log([A⁻]/[HA]). Used to calculate buffer pH and to design buffer systems for specific pH values.
Formula & Notation
Other Names / Synonyms: Henderson-Hasselbalch equation, buffer equation, H-H equation
Properties & Characteristics
Uses & Applications
Safety Information
Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.
Key Facts
Frequently Asked Questions
An equation relating the pH of a buffer solution to the pKa of the weak acid and the ratio of concentrations of the conjugate base to the weak acid: pH = pKa + log([A⁻]/[HA]). Used to calculate buffer pH and to design buffer systems for specific pH values.
The Henderson-Hasselbalch equation is used in: designing buffer solutions for a target pH, calculating pH of a weak acid/conjugate base mixture, determining pKa from pH measurements at known ratios, in pharmaceutical formulation of drugs requiring specific pH, and in biochemical media preparation.
The Henderson-Hasselbalch equation provides pH at equilibrium — the actual rate of pH change when acid or base is added depends on buffer capacity. Using a buffer outside its effective range (pH = pKa ± 1) provides inadequate pH control. Always verify pH with a calibrated electrode.
The formula or notation for Henderson-Hasselbalch Equation is: pH = pKa + log([A⁻]/[HA])