Ph Calculator Titration of Buffer Solution With Sodium

Henderson-Hasselbalch Equation for Buffer Titration:

\[ \text{pH} = \text{pKa} + \log\left(\frac{[\text{base}] + \text{added NaOH}}{[\text{acid}]}\right) \]

pKa:

[Base] (initial concentration):

mol/L

[Acid] (initial concentration):

mol/L

Added NaOH (concentration equivalent):

mol/L

Calculated pH:

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is the Buffer Titration pH Calculation?

The Henderson-Hasselbalch equation calculates the pH of a buffer solution during titration with a strong base (like NaOH). It's particularly useful for understanding how buffers resist pH changes when base is added.

2. How Does the Calculator Work?

The calculator uses the modified Henderson-Hasselbalch equation:

\[ \text{pH} = \text{pKa} + \log\left(\frac{[\text{base}] + \text{added NaOH}}{[\text{acid}]}\right) \]

Where:

\( \text{pKa} \) — Acid dissociation constant of the weak acid
\( [\text{base}] \) — Initial concentration of conjugate base (mol/L)
\( \text{added NaOH} \) — Concentration of strong base added (mol/L equivalent)
\( [\text{acid}] \) — Initial concentration of weak acid (mol/L)

Explanation: The equation shows how added base converts weak acid to conjugate base, changing the buffer ratio and thus the pH.

3. Importance of pH Calculation in Buffer Titration

Details: Understanding pH changes during titration helps in designing effective buffer systems for chemical and biological applications where pH stability is crucial.

4. Using the Calculator

Tips: Enter all concentrations in mol/L. The pKa value should be for the specific acid in your buffer system. Added NaOH should be in equivalents (moles per liter of solution).

5. Frequently Asked Questions (FAQ)

Q1: Why does the equation use (base + NaOH) in the numerator?
A: The added NaOH converts an equivalent amount of weak acid to conjugate base, effectively increasing the base concentration in the buffer.

Q2: What if I add more NaOH than there is acid?
A: This calculator assumes you're within the buffer region. Beyond the equivalence point, you'd need to calculate pH from excess OH- concentration.

Q3: Does this work for polyprotic acids?
A: For polyprotic acids, you'd need to consider multiple pKa values and buffer regions.

Q4: How does temperature affect the calculation?
A: Temperature affects pKa values. Use the pKa appropriate for your experimental temperature.

Q5: What are common buffer systems this applies to?
A: Common examples include acetate (pKa ~4.76), phosphate (pKa ~7.21), and Tris (pKa ~8.07) buffers.