1. What is the Sodium Bicarbonate Buffer Calculator?

Definition: This calculator determines the pH of a buffer solution using the Henderson-Hasselbalch equation, specifically for sodium bicarbonate buffer systems.

Purpose: It helps chemists, biologists, and medical professionals calculate buffer pH for various applications including laboratory work and physiological studies.

2. How Does the Calculator Work?

The calculator uses the Henderson-Hasselbalch equation:

Where:

• pH — Buffer pH (dimensionless)
• pKa — Dissociation constant (dimensionless)
• [A⁻] — Concentration of conjugate base (mol/L)
• [HA] — Concentration of acid (mol/L)

Explanation: The equation relates pH to the ratio of conjugate base to acid concentrations in a buffer solution.

3. Importance of Buffer pH Calculation

Details: Accurate pH calculation is crucial for maintaining stable conditions in chemical reactions, biological systems, and medical applications.

4. Using the Calculator

Tips: Enter the pKa value (6.1 for carbonic acid by default), concentrations of conjugate base and acid. All concentration values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is the pKa for sodium bicarbonate buffer?
A: The pKa for the carbonic acid/bicarbonate buffer system is approximately 6.1 at physiological temperature.

Q2: What are typical concentrations used?
A: Physiological concentrations are about 24 mM bicarbonate and 1.2 mM carbonic acid, giving pH ~7.4.

Q3: When would I need to adjust the pKa value?
A: Adjust pKa for different temperatures or when working with different buffer systems.

Q4: What if my ratio is 1:1?
A: When [A⁻]/[HA] = 1, pH = pKa since log(1) = 0.

Q5: Can this be used for other buffer systems?
A: Yes, but you must use the appropriate pKa value for that specific acid-base pair.