1. What is Buffer Capacity?

Buffer capacity (β) measures how well a solution resists changes in pH when acid or base is added. It's defined as the amount of strong acid or base needed to change the pH of 1 liter of solution by 1 unit.

2. How Does the Calculator Work?

The calculator uses the buffer capacity formula:

Where:

• \( \beta \) — Buffer capacity (mol/L pH)
• \( [HA] \) — Concentration of weak acid (M)
• \( [A^-] \) — Concentration of conjugate base (M)
• \( \ln(10) \) — Natural logarithm of 10 (~2.302585)

Explanation: The equation shows buffer capacity depends on both the acid and conjugate base concentrations and their relative proportions.

3. Importance of Buffer Capacity

Details: Buffer capacity is crucial in biological systems (blood pH maintenance), chemical processes, and laboratory applications where stable pH is required.

4. Using the Calculator

Tips: Enter concentrations of both acid [HA] and conjugate base [A-] in molarity (M). Both values must be ≥0. The calculator will compute the buffer capacity in mol/L pH.

5. Frequently Asked Questions (FAQ)

Q1: What is the maximum buffer capacity?
A: Maximum buffer capacity occurs when [HA] = [A-], at which point β = 0.576×C (where C is total buffer concentration).

Q2: How does buffer capacity change with pH?
A: Buffer capacity is highest near the pKa of the acid-base pair and decreases as pH moves away from pKa.

Q3: What are typical buffer capacity values?
A: Biological buffers typically have β values between 0.01-0.1 mol/L pH. Chemical buffers may have higher capacities.

Q4: Can this formula be used for polyprotic acids?
A: No, this formula is for monoprotic acids only. Polyprotic acids require more complex calculations.

Q5: How does temperature affect buffer capacity?
A: Temperature mainly affects pKa values, which indirectly affects buffer capacity near the pKa.