# Describe how a student would carry out an acid-base titration to find the volume of hydrochloric acid needed to neutralise 25.0 cm³ of sodium hydroxide solution, using an indicator. Include how the student would know when the end-point has been reached.

> Cambridge International IGCSE Chemistry (0620) — 12.2 Acid-base titrations · Describe · 4 marks

## Mark scheme (4 marks)

1. Use a pipette (and pipette filler) to measure 25.0 cm³ of sodium hydroxide solution into a conical flask
2. Add a few drops of a named indicator to the sodium hydroxide solution in the conical flask
3. Fill a burette with hydrochloric acid and add it slowly / dropwise to the conical flask, swirling throughout
4. End-point is when the indicator permanently changes colour (and the change is consistent with a named indicator, e.g. phenolphthalein changes from pink to colourless)

## Key terms

- [titration](https://www.gradenine.co.uk/glossary/titration)
- [end-point](https://www.gradenine.co.uk/glossary/end-point)
- [indicator](https://www.gradenine.co.uk/glossary/indicator)

## Related

- [Revision notes for Cambridge International IGCSE Chemistry (0620)](https://www.gradenine.co.uk/learn)
- [How to answer "Describe" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/describe-how-a-student-would-carry-956564ae) · Published by Druglandscape Ltd.