Created By : Rina Nayak

Reviewed By : Phani Ponnapalli

Last Updated : Apr 03, 2023

Henderson-Hasselbalch Calculator determines the pH of a buffer solution quickly and effortlessly. This free tool takes conjugate base, acid, Ka details to give the concentration of the acid and conjugate base within it.

Conjugate Base[HA-]

Step by Step Process to Find pH

Go through the steps on how to calculate the pH of the solution easily.

  • Get the conjugate base, acid, Ka details.
  • Divide the conjugate base by the acid.
  • Find the logarithm of the value
  • Add it to the pKa to get the solution pH.

Henderson-Hasselbalch Equation

The Henderson-Hasselbalch Equation to calculate the pH of the solution is as follows:

pH = pKₐ + log([A⁻]/[HA])

The parameters required to use the Henderson-Hasselbalch Calculator is along the lines:

[A⁻] is the molar concentration of the conjugate base

[HA] is the molar concentration of the acid

pK is the acid's dissociation constant

The pH formula is pH = -log(H).

A buffer solution contains a strong acid with a weak conjugate base, strong base with a weak conjugate acid.

In simple terms, the acid can be defined as the proton donor. The base is a proton acceptor.


Question: A mixture of 0.2 M acetic acid and 0.3 M sodium acetate is given. Calculate the pH of the medium if pKa of the acid is 4.5.


Given that

The concentration of acetic acid = 0.2 M

The concentration of the acetate ion = 0.3 M


pka of aetic acid = 4.5


pH = pKₐ + log([A⁻]/[HA])

pH = 4.5 + log(0.3/0.2)

= 4.5 + log 1.5

= 4.5 + 0.18

= 4.68

The pH of the given solution is 4.68.

Chemistrycalc.Com has got calculators like Buffer Capacity, Buffer pH, Cell EMF and many more at one place.

FAQ’s on Henderson-Hasselbalch Calculator

1. What is the use of the Henderson-Hasselbalch equation?

The Henderson-Hasselbalch equation is used for calculating the amount of acid or conjugate base to be required for preparing the buffer solution that has a specific pH.

2. How to solve the Henderson-Hasselbalch equation without using a calculator?

The Henderson-Hasselbalch equation is pH = pKₐ + log([A⁻]/[HA]). Place the values in the formula and solve to get the concentration of acid in a buffer solution.

3. What is the pK value?

pK is the measure of the strength of the acid on a logarithmic scale and it is used to compare the strength of various acids. pK = log(1/Ka). Here Ka is the acid dissociation constant.

4. What is the relationship between pK and pKa?

The simple relationship between the pK and pKa is pKa + pKb = 14.

Henderson-Hasselbalch Calculator