# A student carries out a titration to determine the end point of a reaction between ethanoic acid and potassium hydroxide solution. Explain why the student should perform a rough titration first, and then describe how concordant titre values are obtained from subsequent accurate titrations.

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

## Mark scheme (4 marks)

1. The rough titration identifies the approximate end point / volume needed so the accurate titrations can be performed more carefully near the end point
2. The solution is added dropwise / very slowly when approaching the end point (in accurate titrations)
3. The end point is identified by a permanent colour change of the indicator
4. Concordant titres are two or more titre values that agree within 0.10 cm³ (of each other)

## Key terms

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

## Related

- [Revision notes for Cambridge International IGCSE Chemistry (0620)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" 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/a-student-carries-out-a-titration-f49124e7) · Published by Druglandscape Ltd.