Buffer pH Calculator (Henderson–Hasselbalch)

Buffer pH Calculator (Henderson–Hasselbalch)

pKa

unitless

[Acid]

mol/L

[Base]

mol/L

pH

unitless

What is Buffer pH? (Henderson–Hasselbalch Equation)

Buffer solutions play a crucial role in maintaining stable pH in chemical, biological, and pharmaceutical systems. A buffer is typically made of a weak acid and its conjugate base, which resist changes in pH when small amounts of acid or base are added. The pH of such solutions can be accurately calculated using the Henderson–Hasselbalch equation.

The equation is expressed as:
pH = pKa + log₁₀ ([Base] / [Acid])

Here, pKa represents the acid dissociation constant, while [Base] and [Acid] represent the molar concentrations of the conjugate base and weak acid, respectively. This equation is widely used in pharmaceutical sciences, especially in drug formulation, buffer preparation, and biological system analysis.

Understanding buffer pH is essential for maintaining drug stability, optimizing enzyme activity, and ensuring proper physiological conditions. In the human body, buffer systems such as the bicarbonate buffer help maintain blood pH within a narrow range, which is critical for survival.

How to Use the Buffer pH Calculator

• Enter the pKa value of the weak acid.
• Provide the concentration of acid and base.
• Click the Calculate button.
• The tool instantly computes the pH of the buffer solution.

Example Calculation

Consider a buffer solution with:

• pKa = 4.75
• [Base] = 0.1 mol/L
• [Acid] = 0.1 mol/L

Using the equation:
pH = 4.75 + log(0.1 / 0.1) = 4.75

If the base concentration increases, the pH rises, making the solution more basic. Similarly, increasing acid concentration lowers the pH. This balance is critical in pharmaceutical buffers, injections, and biological fluids.

This Buffer pH Calculator is designed for students, researchers, and pharmacists who need quick and accurate results without manual logarithmic calculations. It is especially useful for GPAT, pharmacology studies, and lab work.

Use this advanced chemistry calculator on QuantCal for fast, reliable, and precise buffer pH calculations.