Visualize pH changes during acid-base titrations with interactive curves for strong/weak acid-base combinations including buffer regions and equivalence points.
Equivalence Point pH
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Equivalence Volume
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Initial pH
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pH at Check Volume
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Strong acids dissociate completely in solution, while weak acids only partially dissociate. This creates different curve shapes: strong acid titrations have sharp pH changes at the equivalence point, while weak acid titrations have buffer regions and more gradual pH changes before the equivalence point.
The equivalence point pH depends on the strength of the acid and base. Strong acid + strong base gives pH 7, but weak acid + strong base gives pH > 7 due to the basic salt formed, and strong acid + weak base gives pH < 7 due to the acidic salt formed.
pKa is the negative log of the acid dissociation constant, indicating acid strength. Lower pKa means stronger acid. For weak acids, pKa determines the pH at the half-equivalence point and affects the shape of the buffer region in the titration curve.
The equivalence volume is calculated using stoichiometry: Ve = (CA × VA) / CT, where CA and VA are the analyte concentration and volume, and CT is the titrant concentration. This is the volume needed to neutralize all the analyte.
The buffer region occurs when both the weak acid and its conjugate base are present in significant amounts. This happens before the equivalence point when the base has partially neutralized the acid, creating a mixture that resists pH changes.
These calculations assume ideal conditions and may differ slightly from lab results due to factors like temperature effects, ionic strength, and impurities. However, they provide excellent theoretical predictions for most educational and analytical purposes.
The steepest part occurs around the equivalence point where small additions of titrant cause large pH changes. This is where indicators change color and where the most accurate endpoint detection occurs in practical titrations.