pKa and pH Calculator

pH Value:

Acid Concentration [HA]:

Salt Concentration [A⁻]:

pKa Value:

pH Value:

pOH Value:

[H⁺] Concentration:

[OH⁻] Concentration:

1. What is the pKa and pH Calculator?

Definition: This calculator determines the pKa of a buffer solution based on the pH and the concentrations of a weak acid [HA] and its conjugate base [A⁻], using the Henderson-Hasselbalch equation.

Purpose: It helps chemists, students, and researchers calculate pKa from pH for buffer solutions, useful in chemistry, biology, and environmental science for understanding acid-base equilibria.

2. How Does the Calculator Work?

The calculator uses the Henderson-Hasselbalch equation:

\[ \text{pH} = \text{pK}_a + \log_{10}\left(\frac{[\text{A}^-]}{[\text{HA}]}\right) \]

Where:

\( \text{pH} \) — The pH value of the solution (user-provided).
\( \text{pK}_a \) — Negative logarithm of the acid dissociation constant (calculated).
\( [\text{HA}] \) — Concentration of the weak acid.
\( [\text{A}^-] \) — Concentration of the conjugate base.
Units for concentrations can be M, mM, or µM.

Explanation: Enter the pH value, input the acid and salt concentrations with their units, and click "Calculate." Results show pKa, pH, pOH, [H⁺], and [OH⁻], with values < 0.00001 displayed in scientific notation.

3. Importance of pKa and pH Calculation

Details: Understanding pKa and pH is crucial for analyzing buffer systems, chemical reactions, and biological processes. Accurate calculations ensure reliable pH control in experiments and applications.

4. Using the Calculator

Tips: Enter a valid pH value (0 to 14), input positive concentrations with consistent units (M, mM, or µM), and click "Calculate." Ensure concentrations are accurate for precise pKa calculation.

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