Buffer Capacity
Buffer effect
Buffer capacity β quantifies how much strong acid/base is needed to change pH.
β = dn / dpH
dn = β × dpH
dpH = dn / β
- High β: stable pH
- Maximum near pKa
- Important in labs and biochemistry
Formulas
β = dn / dpH
dn = β × dpH
dpH = dn / β
Examples
β calculation
dn=0.01; dpH=0.5
β=0.02 mol/(L·pH)
dn=0.01; dpH=0.5
β=0.02 mol/(L·pH)
required dn
β=0.03; dpH=0.2
dn=0.006 mol/L
β=0.03; dpH=0.2
dn=0.006 mol/L
pH shift
dn=0.01; β=0.05
dpH=0.2
dn=0.01; β=0.05
dpH=0.2
Practical use
Higher β means stronger resistance to pH changes.
Higher β means stronger resistance to pH changes.
Technical Background
Interpretation
β is a differential quantity depending on current pH and buffer composition.
Applications
- Preparing stable buffers
- Biochemical assays
- Process and environmental analytics
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