1. What is the Henderson-Hasselbalch Equation?

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

2. How Does the Calculator Work?

The calculator uses the Henderson-Hasselbalch equation:

Where:

• \( pH \) — pH value (dimensionless)
• \( pKa \) — Acid dissociation constant (dimensionless)
• \( \text{moles base} \) — Moles of conjugate base (mol)
• \( \text{moles acid} \) — Moles of weak acid (mol)

Explanation: The equation calculates the pH of a buffer solution based on the ratio of base to acid concentrations and the acid's dissociation constant.

3. Importance of pH Calculation in Titration

Details: Accurate pH calculation is crucial for understanding buffer capacity, predicting equivalence points, and analyzing titration curves in acid-base chemistry.

4. Using the Calculator

Tips: Enter pKa value, moles of base, and moles of acid. All values must be valid (moles acid > 0, moles base ≥ 0).

5. Frequently Asked Questions (FAQ)

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

Q2: What are typical pKa values for common acids?
A: Acetic acid: 4.76, Phosphoric acid: 2.15, 7.20, 12.35, Carbonic acid: 6.35, 10.33.

Q3: Can this equation be used for strong acid-strong base titrations?
A: No, the Henderson-Hasselbalch equation is specifically designed for weak acid-base systems and buffer solutions.

Q4: What are the limitations of this equation?
A: The equation assumes ideal behavior and may not be accurate for very dilute solutions or when ionic strength effects are significant.

Q5: How does temperature affect the calculation?
A: pKa values are temperature-dependent, so calculations should use pKa values measured at the appropriate temperature.