1. What is the Henderson-Hasselbalch Equation?

The Henderson-Hasselbalch equation relates the pH of a buffer solution to the pKa of the acid and the ratio of the concentrations of the salt (conjugate base) and the acid. It's fundamental in chemistry and biochemistry for preparing buffer solutions.

2. How Does the Calculator Work?

The calculator uses the Henderson-Hasselbalch equation:

Where:

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

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

3. Importance of Buffer pH Calculation

Details: Accurate pH calculation is crucial for preparing effective buffer solutions used in chemical reactions, biological systems, and laboratory experiments to maintain stable pH conditions.

4. Using the Calculator

Tips: Enter pKa value, salt concentration and acid concentration in molarity (M). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is the valid range for buffer pH calculations?
A: The equation works best when pH is within ±1 unit of the pKa, where the buffer has good capacity.

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

Q3: What are common buffer systems?
A: Common systems include acetic acid/acetate (pKa 4.76), phosphate (pKa 7.21), and Tris (pKa 8.07).

Q4: Does temperature affect the calculation?
A: Yes, pKa values are temperature-dependent, so use the pKa value at your working temperature.

Q5: How precise is this calculation?
A: It's a good approximation but doesn't account for ionic strength effects. For precise work, measure pH experimentally.