Acidity Constant (Ka) Calculator

Formula

The formula to calculate the Acidity Constant (Ka) is:

\[ K_a = \frac{[H^+][A^-]}{[HA]} \]

Where:

\( K_a \) is the acidity constant
\( [H^+] \) is the concentration of hydrogen ions in moles per liter (M)
\( [A^-] \) is the concentration of the conjugate base in moles per liter (M)
\( [HA] \) is the concentration of the weak acid in moles per liter (M)

Definitions

Acidity Constant (Ka): A quantitative measure of the strength of an acid in solution. It is the equilibrium constant for the dissociation of a weak acid into its conjugate base and a hydrogen ion.
Concentration of Hydrogen Ions ([H+]): The concentration of hydrogen ions in the solution.
Concentration of Conjugate Base ([A–]): The concentration of the conjugate base in the solution.
Concentration of Weak Acid ([HA]): The concentration of the weak acid in the solution.

Example

Let's say the concentration of hydrogen ions ([H+]) is 0.01 M, the concentration of the conjugate base ([A–]) is 0.02 M, and the concentration of the weak acid ([HA]) is 0.1 M. Using the formula:

\[ K_a = \frac{0.01 \times 0.02}{0.1} \]

We get:

\[ K_a = 0.002 \]

So, the acidity constant (Ka) is 0.002.