Henderson-Hasselbalch Calculator
Apply the Henderson-Hasselbalch equation to compute the pH of a buffer or ratio of components.
Calculation Parameters
Adjust the values below.
Calculated Result
Expert Tip
Ensure units are correctly formatted (e.g. Kelvin for gas temperatures and liters for volumes) to get chemically accurate outputs.
How this Calculator Works
This calculator allows you to solve Henderson-Hasselbalch problems dynamically. Adjust the input parameters using the sliders or selection menu below:
- Acid Concentration (M) (Range: 0.01 to 2.00, Default: 0.10)
- Base Concentration (M) (Range: 0.01 to 2.00, Default: 0.20)
- pKa (Range: 0 to 14, Default: 5.00)
The results are computed instantly and updated in the results panel on the right.
Formula & Methodology
Where:
- Acid Concentration: Parameter value.
- Base Concentration: Parameter value.
- pKa: Parameter value.
Step-by-Step Calculation Example
To calculate Henderson-Hasselbalch manually, follow these steps:
- Identify the input parameters. For example:
- Acid Concentration (M) = 0.10
- Base Concentration (M) = 0.20
- pKa = 5.00
- Apply the formula:
pH = pKa + log10([Base] / [Acid])
- Verify the calculated value which is updated instantly in the results panel on the right.
Frequently Asked Questions
What is the Henderson-Hasselbalch equation? ▼
pH = pKa + log10([A-] / [HA]), where [A-] is conjugate base and [HA] is weak acid.
When is pH equal to pKa? ▼
pH equals pKa when [A-] = [HA], meaning the weak acid is 50% ionized.
What are the limitations of the Henderson-Hasselbalch equation? ▼
It assumes negligible water autoionization and holds best for moderate concentrations (1 mM to 1 M).