Calculate Ph Of Buffer Solution Composed Of 0.1m Weak Base

Buffer Solution pH Formula:

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

Calculated pH:

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1. What is the Buffer Solution pH Calculation?

The Henderson-Hasselbalch equation calculates the pH of a buffer solution composed of a weak base and its conjugate acid. For equal concentrations (0.1M each), the pH equals the pKa of the conjugate acid.

2. How Does the Calculator Work?

The calculator uses the Henderson-Hasselbalch equation:

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

For equal concentrations (0.1M weak base and 0.1M conjugate acid):

\( [\text{base}] = 0.1 \) mol/L
\( [\text{acid}] = 0.1 \) mol/L
\( \frac{[\text{base}]}{[\text{acid}]} = 1 \)
\( \log(1) = 0 \)
Therefore: \( \text{pH} = \text{pKa} \)

Explanation: When concentrations of weak base and its conjugate acid are equal, the log term becomes zero, making pH equal to pKa.

3. Importance of Buffer pH Calculation

Details: Buffer solutions resist pH changes when small amounts of acid or base are added. Accurate pH calculation is essential for biochemical experiments, pharmaceutical formulations, and industrial processes where pH stability is critical.

4. Using the Calculator

Tips: Enter the pKa value of the conjugate acid. The calculator will compute the pH of the buffer solution with equal concentrations (0.1M) of weak base and conjugate acid.

5. Frequently Asked Questions (FAQ)

Q1: Why does pH equal pKa when concentrations are equal?
A: Because the log([base]/[acid]) term becomes log(1) = 0, simplifying the equation to pH = pKa.

Q2: What is the range of valid pKa values?
A: pKa values typically range from 0-14 for most weak acids, though some compounds may have values outside this range.

Q3: Can this calculator be used for different concentrations?
A: This specific calculator is designed for equal concentrations (0.1M each). For different concentrations, the full Henderson-Hasselbalch equation must be used.

Q4: What are common weak base-conjugate acid pairs?
A: Common pairs include ammonia/ammonium (pKa = 9.25), pyridine/pyridinium (pKa = 5.25), and Tris/Tris-H+ (pKa = 8.07).

Q5: How accurate is this calculation?
A: The calculation provides a good estimate, but actual pH may vary slightly due to ionic strength effects and temperature variations.