Free · Mixtures and solutions calculators ⚗️

Average Buffer Capacity for Base Addition

Calculate the positive average amount of added strong base per liter per unit rise in pH.

Calculator inputs

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Enter the known values in the units shown. Results update as you type.
Where results are editable, change one to solve backwards. Lock a value to hold it fixed.
Use the worked example to check the method. Reset restores the starting fields.

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Adding 0.1 mol/L of strong base while pH rises from 7 to 8 gives an average capacity of 0.1 mol/L per unit pH.

β = Δb / (pH_final − pH_initial).

Enter these known values and leave the other values blank.

Enter added strong-base concentration in mol/L, not a total volume of reagent. Divide added moles by the modeled solution volume before entering it.
This finite-difference estimate applies to a positive pH rise. Acid addition requires a different sign convention; this tool restricts final pH above initial pH.
The model supports pH from 0 to 14 as an explicit input range. Real activity-based pH is not universally limited to that interval.
A zero pH change cannot determine finite capacity. The result is an average across the interval, not a derivative at one pH.

Convert it to added moles per liter of modeled solution first.

No. It divides a finite added concentration by a finite pH change.

Declare the physical or stated approximation domain; captured arithmetic is unchanged.