IB Chemistry - Acids and Bases

IB Chemistry home > Syllabus 2025 > Acids and Bases > Titration curves

The shape of the 'pH against volume added' graph differs depending on the type of acid and base.

Syllabus reference

Reactivity 3.1.13 - pH curves of different combinations of strong and weak monoprotic acids and bases have characteristic shapes and features. (HL)

  • Interpret the general shapes of pH curves for all four combinations of strong and weak acids and bases.

Guidance

  • Interpretation should include: intercept with the pH axis, equivalence point, buffer region, points where pH = pKa or pOH = pKb.

Tools and links

  • Tool 1 - When collecting data to generate a pH curve, when should smaller volumes of titrant be added between each measurement?

Strong acid - strong base titrations

Titration curves are the graphs obtained by plotting the pH of the reaction mixture against the volume of base (or acid) added during the titration of either an acid by a base or vice versa.

A typical strong acid - strong base titration curve looks like as follows:

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Weak acid - strong base titration

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Weak base strong acid titration

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Weak acid with a weak base

This mixture cannot be titrated as the change in pH near the equivalence point is too small to allow reliable results.
ColSol Testing

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