Ph Of Buffer Solution Calculator

Henderson-Hasselbalch Equation:

\[ pH = pKa + \log\left(\frac{[A^-]}{[HA]}\right) \]

Calculated pH:

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1. What is the Henderson-Hasselbalch Equation?

The Henderson-Hasselbalch equation is a chemical expression that relates the pH of a buffer solution to the acid dissociation constant (pKa) and the ratio of concentrations of the conjugate base ([A⁻]) to the weak acid ([HA]). It provides a simple way to calculate the pH of buffer solutions.

2. How Does the Calculator Work?

The calculator uses the Henderson-Hasselbalch equation:

\[ pH = pKa + \log\left(\frac{[A^-]}{[HA]}\right) \]

Where:

\( pH \) — The calculated pH of the buffer solution (dimensionless)
\( pKa \) — The acid dissociation constant (dimensionless)
\( [A^-] \) — Concentration of the conjugate base
\( [HA] \) — Concentration of the weak acid
\( \frac{[A^-]}{[HA]} \) — Ratio of concentrations (dimensionless)

Explanation: The equation shows that the pH of a buffer solution depends on the pKa of the weak acid and the logarithm of the ratio between the conjugate base and acid concentrations.

3. Importance of pH Calculation in Buffer Solutions

Details: Accurate pH calculation is crucial for understanding and predicting the behavior of buffer solutions, which are essential in many chemical and biological systems for maintaining stable pH conditions.

4. Using the Calculator

Tips: Enter the pKa value and the concentration ratio ([A⁻]/[HA]). Both values must be valid (ratio > 0). The calculator will compute the pH using the Henderson-Hasselbalch equation.

5. Frequently Asked Questions (FAQ)

Q1: What is a buffer solution?
A: A buffer solution is an aqueous solution consisting of a mixture of a weak acid and its conjugate base, or vice versa, that resists pH change when small amounts of acid or base are added.

Q2: When is the Henderson-Hasselbalch equation most accurate?
A: The equation is most accurate when the concentrations of the acid and conjugate base are significantly larger than the concentration of H⁺ or OH⁻ ions, typically when the ratio is between 0.1 and 10.

Q3: What are common applications of buffer solutions?
A: Buffer solutions are used in chemical laboratories, biological research, pharmaceutical preparations, and many industrial processes where maintaining a constant pH is important.

Q4: What are the limitations of the Henderson-Hasselbalch equation?
A: The equation assumes ideal behavior and may not be accurate for very dilute solutions, very concentrated solutions, or when the acid is very strong or very weak.

Q5: Can this equation be used for basic buffer solutions?
A: Yes, the equation can be adapted for basic buffers by using pKb instead of pKa and the appropriate ratio of concentrations.