1. What is the Henderson-Hasselbalch Equation?

The Henderson-Hasselbalch equation is used to estimate the pH of a buffer solution during acid-base titrations. It relates pH, pKa (acid dissociation constant), and the ratio of the concentrations of the conjugate base and weak acid.

2. How Does the Calculator Work?

The calculator uses the Henderson-Hasselbalch equation:

Where:

• \( pH \) — Resulting pH value (dimensionless)
• \( pKa \) — Acid dissociation constant (dimensionless)
• \( added \) — Concentration of added titrant (mol/L)
• \( remaining \) — Concentration of remaining acid/base (mol/L)

Explanation: The equation calculates the pH of a solution during titration based on the ratio of added titrant to remaining acid/base.

3. Importance of pH Calculation in Titration

Details: Accurate pH calculation is crucial for determining the equivalence point in titrations, understanding buffer capacity, and predicting solution behavior during acid-base reactions.

4. Using the Calculator

Tips: Enter pKa value, added concentration, and remaining concentration. All values must be positive numbers. The calculator will compute the resulting pH using the logarithmic relationship.

5. Frequently Asked Questions (FAQ)

Q1: When is the Henderson-Hasselbalch equation most accurate?
A: The equation is most accurate when the concentrations of acid and conjugate base are within a factor of 10 of each other (0.1 < ratio < 10).

Q2: What are the limitations of this equation?
A: It assumes ideal behavior, neglects activity coefficients, and becomes less accurate for very dilute solutions or extreme pH values.

Q3: Can this equation be used for strong acid-strong base titrations?
A: The Henderson-Hasselbalch equation is primarily for weak acid/weak base systems. For strong acid-strong base titrations, different calculations are needed.

Q4: How does temperature affect the calculation?
A: Temperature affects both pKa values and the autoprotolysis constant of water, which should be considered for precise calculations.

Q5: What units should be used for concentration values?
A: While the ratio is dimensionless, concentrations should be entered in consistent units (typically mol/L) for accurate results.