1. What is the Henderson-Hasselbalch Equation?

The Henderson-Hasselbalch equation relates the pH of a solution to the pKa of the acid and the ratio of the concentrations of the conjugate base and acid forms. It's particularly useful for buffer solutions and estimating the pH of weak acid solutions.

2. How Does the Calculator Work?

The calculator uses the Henderson-Hasselbalch equation:

Where:

• \( pH \) — The calculated pH of the solution
• \( pKa \) — The acid dissociation constant
• \( [base] \) — Concentration of the conjugate base (M)
• \( [acid] \) — Concentration of the weak acid (M)

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

3. Importance of Buffer pH Calculation

Details: Accurate pH calculation is crucial for preparing buffer solutions in biochemical and chemical experiments, maintaining stable pH conditions, and understanding acid-base equilibria.

4. Using the Calculator

Tips: Enter the pKa value of your weak acid, the concentration of the conjugate base, and the concentration of the weak acid. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is the valid range for this equation?
A: The equation works best when the ratio [base]/[acid] is between 0.1 and 10 (pH within ±1 unit of pKa).

Q2: Can I use this for strong acids or bases?
A: No, this equation is only valid for weak acid/conjugate base systems.

Q3: What units should I use for concentrations?
A: Use molarity (M) for both base and acid concentrations.

Q4: Why is my calculated pH different from my measured pH?
A: Activity coefficients, temperature effects, and ionic strength can cause deviations between calculated and measured pH.

Q5: How can I prepare a buffer at a specific pH?
A: Use this equation to determine the required ratio of base to acid for your desired pH, then adjust concentrations to achieve appropriate buffer capacity.