Buffer capacity calculator

How to use the calculator

1. Enter the concentration of your weak acid (HA) in molar (M) units.
2. Enter the concentration of your conjugate base (A⁻) in molar (M) units.
3. Enter the pKa value of your weak acid. This can be found in chemical reference tables.
4. Enter the total volume of your buffer solution in liters (L).
5. Click the "Calculate" button to compute the buffer capacity and optimal pH range.
6. Click "Reset" to clear all inputs and start over.

Understanding Buffer Capacity

Buffer capacity (β) is a measure of the amount of acid or base that can be added to a buffer solution before a significant change in pH occurs. It's expressed in moles per liter (M/L).

The higher the buffer capacity, the more resistant the solution is to pH changes. A buffer with a capacity of 1 M/L can neutralize 1 mole of added acid or base per liter of solution before the pH changes by 1 unit.

Working Principle

This calculator uses the following formula to determine buffer capacity:

β = (2 × C_A × C_B) / (C_A + C_B) × 10^pKa

Where:

• β = Buffer capacity
• C_A = Concentration of weak acid (HA)
• C_B = Concentration of weak base (A⁻)
• pKa = Acid dissociation constant

Optimal pH Range

The optimal pH range for a buffer is typically within one pH unit of its pKa value (pH = pKa ± 1). Within this range, the buffer is most effective at resisting pH changes.

Applications

Buffer capacity calculations are essential in various fields:

• Biological systems (maintaining blood pH)
• Chemical experiments requiring stable pH conditions
• Pharmaceutical formulations
• Environmental monitoring