Who this is for: Cambridge IGCSE Chemistry (0620) students who want acid–base titrations — burette readings, indicators and neutralisation — to become precise Paper 6 and structured-question marks instead of vague “add until colour changes” answers.
What query it owns: how to understand and revise acid–base titrations in Cambridge IGCSE Chemistry.
Why this is safe: this page owns the acid–base titrations revision-guide angle, while Tutopiya’s Acid–Base Titrations subtopic page owns the learning resource.

Acid–base titration is a practical technique to find the concentration of an acid or alkali by neutralisation with a solution of known concentration. Cambridge IGCSE Chemistry (0620) tests the apparatus (pipette, burette, conical flask), indicators (methyl orange, phenolphthalein), how to read a titre, and simple neutralisation calculations. This guide covers the method step by step and the mistakes that cost marks every series.

Key takeaways

• A pipette delivers a fixed, accurate volume of alkali into a conical flask.
• A burette delivers variable volumes of acid — read the meniscus at eye level.
• Titre = volume of acid added from burette to reach the end point.
• Methyl orange: yellow in alkali → red in acid; phenolphthalein: pink in alkali → colourless in acid.
• Do a rough titration first, then at least two concordant titres (within 0.10 cm³).

What are acid–base titrations in Cambridge IGCSE Chemistry?

Titration determines the volume of one solution needed to neutralise a known volume of another. The end point is shown by a colour change of an indicator. The syllabus requires you to describe the procedure, read apparatus correctly, and carry out mole-ratio calculations from balanced equations.

Read the full notes on Tutopiya’s Acid–Base Titrations subtopic page before attempting questions.

The core ideas you must master

Apparatus / term	Purpose	Key detail
Pipette (e.g. 25 cm³)	Deliver fixed volume of alkali	Rinse with alkali; use pipette filler
Burette (50 cm³)	Deliver variable volume of acid	Rinse with acid; read meniscus at eye level
Conical flask	Holds alkali + indicator	Swirl during addition
Indicator	Shows end point	2–3 drops only
Titre	Volume of acid used	From initial to final burette reading
Concordant titres	Within 0.10 cm³	Use mean of concordant values only

Indicators for acid–base titrations

Indicator	Colour in alkali	Colour at end point (acid added)	Best for
Methyl orange	Yellow	Red / orange-red	Strong acid + strong alkali
Phenolphthalein	Pink	Colourless	Strong alkali titrated with acid
Litmus	Blue	Red (in acid)	General indicator

Titration procedure — step by step

1. Rinse pipette with alkali; transfer 25.0 cm³ alkali to a conical flask.
2. Add 2–3 drops of indicator.
3. Fill burette with acid; record initial reading.
4. Add acid gradually while swirling until indicator just changes colour (end point).
5. Record final reading; titre = final − initial.
6. Repeat until at least two concordant titres; calculate the mean.

Acid–base titrations in past-paper wording: command words that matter

Command word	What the question wants	Typical titration stem
Describe	Full procedure	”Describe how to carry out a titration.”
State	Apparatus or observation	”State the colour change at the end point with phenolphthalein.”
Calculate	Concentration from titre data	”Calculate the concentration of the acid.”
Suggest	Improvement or error source	”Suggest why the titre values are not concordant.”
Read	Burette reading	”Read the burette diagram and state the titre.”

Worked exam-style stems (how to answer the wording)

1. “Describe how to carry out a titration to find the concentration of hydrochloric acid.” Use a pipette to transfer 25.0 cm³ of sodium hydroxide into a conical flask. Add indicator. Fill a burette with HCl and record the initial reading. Add acid while swirling until the indicator just changes colour. Record the final reading; titre = difference. Repeat for concordant results. Reward: pipette + burette + indicator + swirling + repeat.
2. “State the colour change when phenolphthalein is used to titrate NaOH with HCl.” Pink to colourless at the end point. Reward: both colours in correct order.
3. “25.0 cm³ of 0.100 mol/dm³ NaOH neutralises 23.5 cm³ of HCl. Calculate the concentration of HCl.” Moles NaOH = 0.100 × 25.0/1000 = 0.00250 mol. Moles HCl = 0.00250 mol (1:1 ratio). Conc HCl = 0.00250 ÷ (23.5/1000) = 0.106 mol/dm³. Reward: moles calculation + concentration with units.

Work through examples on Tutopiya’s Acid–Base Titrations subtopic page.

How titrations connect to the rest of the course

Titrations link to Acids, Bases and Salts (neutralisation), Moles (calculations) and Experimental Design (reliability). The Cambridge IGCSE Chemistry resource hub links all units.

Common mistakes students make

• Reading the burette above or below eye level — read the meniscus at eye level.
• Using the mean of all titres instead of concordant titres only.
• Adding too much indicator — 2–3 drops only.
• Forgetting to swirl the conical flask during addition.
• Confusing pipette (fixed volume) with burette (variable volume).

When you need more support

If titre calculations and procedure descriptions keep costing marks, work through the Acid–Base Titrations subtopic page, then get focused help from a Cambridge IGCSE Chemistry tutor.

Frequently asked questions

What is the difference between a pipette and a burette? A pipette delivers one fixed accurate volume; a burette delivers variable volumes and is used to measure the titre.

What are concordant titres? Titre values within 0.10 cm³ of each other — only these are used to calculate the mean.

Which indicator is used for titrating NaOH with HCl? Methyl orange or phenolphthalein — phenolphthalein changes from pink to colourless.

How do I revise acid–base titrations effectively? Learn the procedure with apparatus names, practise indicator colour changes and titre calculations, then apply to Paper 6 stems.

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