The focus here is on what happens when the titration results are plotted – differences in graphs or titration curves with strong or weak acids or alkalis. Practical titration techniques and good practice are considered in the topic, Titrations. Consider the following titration curve of HCl added to NaOH, with both reagents being equimolar.

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Consider why is the initial pH high?

The pH is initially high due to the strong alkali.

Why does the pH fall slowly?

The pH falls very slowly because of the logarithmic scale. Only when 90% of the alkali is neutralised will the pH be one unit lower.

Why is there a sharp drop in pH?

When 99% of the alkali has been neutralised, the pH will be two units lower (not acounting for any effect of dilution). A subsequent drop of acid will neutralise the remaining few OH^– ions giving the sudden drop in pH.

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[interactive matching titration curves to get users to think about other combinations. Since we cannot ask them to draw the curves here, matching them correctly at least gets them to think about what each one should look like rather than giving a list]