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.

Extended information about "Acidity-Constant-Ka-Calculator"

Calculate Ka of Weak Acid from pH

Definition: The acid dissociation constant (Ka) measures the strength of a weak acid in solution.

Formula: \( K_a = \frac{[H^+][A^-]}{[HA]} \)

\( K_a \): Acid dissociation constant
\( [H^+] \): Concentration of hydrogen ions
\( [A^-] \): Concentration of conjugate base
\( [HA] \): Concentration of the acid

Example: \( K_a = \frac{10^{-3} \times 10^{-3}}{0.1} \)

\( K_a \): Acid dissociation constant
\( [H^+] \): \( 10^{-3} \) M
\( [A^-] \): \( 10^{-3} \) M
\( [HA] \): 0.1 M

How to Calculate Ka of Acetic Acid

Definition: Acetic acid is a weak acid, and its dissociation in water can be described by its Ka value.

Formula: \( K_a = \frac{[H^+][CH_3COO^-]}{[CH_3COOH]} \)

\( K_a \): Acid dissociation constant
\( [H^+] \): Concentration of hydrogen ions
\( [CH_3COO^-] \): Concentration of acetate ions
\( [CH_3COOH] \): Concentration of acetic acid

Example: \( K_a = \frac{10^{-4} \times 10^{-4}}{0.05} \)

\( K_a \): Acid dissociation constant
\( [H^+] \): \( 10^{-4} \) M
\( [CH_3COO^-] \): \( 10^{-4} \) M
\( [CH_3COOH] \): 0.05 M

Ka Acid Dissociation Constant

Definition: The acid dissociation constant (Ka) quantifies the strength of an acid in solution.

Formula: \( K_a = \frac{[H^+][A^-]}{[HA]} \)

\( K_a \): Acid dissociation constant
\( [H^+] \): Concentration of hydrogen ions
\( [A^-] \): Concentration of conjugate base
\( [HA] \): Concentration of the acid

Example: \( K_a = \frac{10^{-5} \times 10^{-5}}{0.2} \)

\( K_a \): Acid dissociation constant
\( [H^+] \): \( 10^{-5} \) M
\( [A^-] \): \( 10^{-5} \) M
\( [HA] \): 0.2 M

pH from Ka Calculation

Definition: The pH of a solution can be calculated using the Ka value of the acid and the concentrations of the species involved.

Formula: \( \text{pH} = -\log[H^+] \)

pH: The measure of acidity
\( [H^+] \): Concentration of hydrogen ions

Example: \( \text{pH} = -\log(10^{-3}) \)

pH: The measure of acidity
\( [H^+] \): \( 10^{-3} \) M