Pipette, indicator, burette, end point. Read the scale the right way.
A titration with an indicator comes up in almost every 0620 Paper 6. Here you titrate 25.0 cm³ of aqueous sodium hydroxide with two acids, R and S, using methyl orange, to find which acid is more concentrated. Watch the set-up built step by step, then build it yourself and check it against the points the examiners look for.
Past-paper referenceOriginal experiment, wording and figures, written in the style of Cambridge IGCSE Chemistry 0620 Paper 6 (Alternative to Practical). It is not copied from a past paper. The “what the examiners said” notes are our paraphrase of the Principal Examiner Reports for Teachers.
Practise next: 0620/62 February/March 2024, (comparing two acids by titration with aqueous sodium carbonate) · official past papers
Practise next: 0620/61 May/June 2023, (titration with a white tile, rinsing and a volumetric pipette) · official past papers
Practise next: 0620/62 October/November 2025, (burette readings, rinsing and comparing two solutions) · official past papers
Examiner reports used: 0620 June 2023, November 2023, March 2024, June 2024 and November 2025.
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What a full-mark diagram shows
Measuring the alkali
25.0 cm³ volumetric pipette with a pipette filler: more accurate than a measuring cylinder. Not a dropping pipette.
The indicator
A few drops of methyl orange (or thymolphthalein). It changes colour sharply at the end point; universal indicator does not.
The titration
Burette clamped vertically and rinsed with the acid, conical flask swirled on a white tile, drop by drop near the end point.
Recording
Initial and final readings at eye level, bottom of the meniscus, all to 0.1 cm³; titre = final − initial.
Habits the examiner reports keep asking for
Burette numbers increase downwards. Do not read the scale upwards like a measuring cylinder.
Write 21.0, not 21. Every burette reading to the same number of decimal places.
The white tile makes the colour change easier to see, not “lets you see the colour”.
Smaller titre, more concentrated acid. Divide the bigger titre by the smaller one.
Give the colour change from and to: methyl orange goes from yellow to orange when acid is added to alkali.