What Is the Henderson-Hasselbalch Buffer Capacity & pH Calculator?
The Henderson-Hasselbalch equation describes the pH of buffer solutions in biological, chemical, and pharmaceutical systems.
How Does the Henderson-Hasselbalch Buffer Capacity & pH Calculator Work?
Added strong acid is neutralized by conjugate base [A⁻], while added strong base is neutralized by weak acid [HA], stabilizing hydronium equilibrium.
Henderson-Hasselbalch Buffer Capacity & pH Calculator Formula & Variables
The core mathematical equation utilized by this calculator is expressed as:
\text{pH} = \text{p}K_a + \log_{10}\left(\frac{[\text{A}^-]}{[\text{HA}]}\right), \quad \beta = 2.303 \cdot \frac{[\text{HA}][\text{A}^-]}{[\text{HA}] + [\text{A}^-]}
Buffer pH depends on pKa and base-to-acid ratio. Van Slyke buffer capacity β peaks at pH = pKa where [A-] = [HA].
How to Use the Henderson-Hasselbalch Buffer Capacity & pH Calculator
- Enter the weak acid pKa.
- Specify weak acid and conjugate base molar concentrations.
Step-by-Step Example Calculation
Acetic Acid Equimolar Buffer
Input Values:
pKa:4.76
acidConc:0.1
baseConc:0.1
Worked Steps: An acetate buffer with 0.1 M acetic acid and 0.1 M acetate has pH = 4.76 and a maximum buffer capacity β = 0.115 mol/(L·pH).
Understanding Your Result
Buffer Solution pH: Exact equilibrium pH value.
Buffer Capacity (β): Moles of strong acid/base required to shift 1 liter of solution by 1 pH unit.
Factors That Affect the Result
- Total buffer concentration and acid-base equimolar symmetry.
When Should You Use This Calculator?
- Cell culture media preparation, enzyme kinetics assays, and blood physiological pH modeling.
Assumptions & Limitations
- Valid when autoionization of water is negligible compared to buffer concentrations.
Frequently Asked Questions
Calculation Accuracy & Reference Note
Standard Van Slyke analytical buffer formulation.