Titrations Made Visual – Colour Change at the Exact Point 

Titrations are a classic of GCSE and A-Level chemistry — but they can feel fiddly until students see the dramatic moment of colour change that marks the end point.

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🧪 The Setup

In a titration, a solution of known concentration (the titrant) is slowly added to a solution of unknown concentration until the reaction is complete. A few drops of an indicator show when this exact point has been reached.

• Acid into alkali? Use phenolphthalein (pink to colourless) or methyl orange (orange to red).

• The burette lets students deliver the titrant drop by drop, making the moment of colour change sudden and satisfying.

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🎨 Why the Colour Change Matters

At the end point, just enough acid has neutralised the alkali (or vice versa). The sharp switch in colour marks the stoichiometric balance:

$$\text{Acid} + \text{Base} \; → \; \text{Salt} + \text{Water}$$

This visual signal is what allows students to calculate the concentration of the unknown solution.

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📊 Making it Precise

Students quickly learn to:

• Repeat titrations until results are within 0.1 cm³.

• Ignore the “rough” first titration, then average the concordant ones.

• Record burette readings carefully to 2 decimal places.

It’s precision work that introduces good scientific habits.

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🎓 Why It Works in Teaching

• Visual learning – the colour change makes neutralisation real.

• Practical skills – accurate measurement, recording, and repeatability.

• Maths link – stoichiometry, molar calculations, and proportional reasoning.

Titrations combine chemistry, maths, and methodical lab work — all signalled by that satisfying colour change at the exact point.