1. What is the Henderson-Hasselbalch Equation?

The Henderson-Hasselbalch equation is used to estimate the pH of a buffer solution from the pKa of the acid and the concentrations of the acid and its conjugate base. It provides a simple way to calculate and prepare buffer solutions with desired pH values.

2. How Does the Calculator Work?

The calculator uses the Henderson-Hasselbalch equation:

Where:

• \( pKa \) — Acid dissociation constant
• \( [A^-] \) — Concentration of conjugate base (M)
• \( [HA] \) — Concentration of weak acid (M)

Explanation: The equation relates pH, pKa, and the ratio of conjugate base to acid concentration in a buffer system.

3. Importance of Buffer pH Calculation

Details: Accurate pH calculation is crucial for preparing buffer solutions in biochemical experiments, pharmaceutical formulations, and various analytical procedures where maintaining stable pH is essential.

4. Using the Calculator

Tips: Enter pKa value, base concentration in M, and acid concentration in M. All concentrations must be positive values.

5. Frequently Asked Questions (FAQ)

Q1: What is the valid range for the Henderson-Hasselbalch equation?
A: The equation works best when the pH is within ±1 unit of the pKa value (effective buffer range).

Q2: Can I use this equation for strong acids or bases?
A: No, the Henderson-Hasselbalch equation is specifically designed for weak acid-base buffer systems.

Q3: What units should I use for concentrations?
A: Use molarity (M) for both acid and base concentrations. The units cancel out in the ratio.

Q4: How accurate is this calculation?
A: The calculation provides a good estimate, but actual pH may vary due to ionic strength effects and temperature variations.

Q5: Can I calculate buffer ratio from desired pH?
A: Yes, the equation can be rearranged to calculate the required ratio of [A-]/[HA] for a target pH.