# A manufacturer produces two versions of a paint: one described as a 'pure pigment' and one described as a 'formulation'. Explain how paper chromatography could be used to distinguish between the pure pigment and the formulation, and describe what the results would show for each sample.

> WJEC A-Level Chemistry (Wales) — 1.2 Electronic structure · Explain · 5 marks

> A manufacturer produces two versions of a paint: one described as a 'pure pigment' and one described as a 'formulation'. Both samples are dissolved in a suitable solvent and spotted onto chromatography paper.

## Mark scheme (5 marks)

1. The solvent (mobile phase) carries the substances up the chromatography paper (stationary phase)
2. Substances separate because they differ in how soluble they are in the mobile phase / how strongly they are attracted to the stationary phase
3. The pure pigment would produce a single spot on the chromatogram
4. The formulation would produce more than one spot because it contains more than one compound / is a mixture
5. Rf values (distance moved by substance divided by distance moved by solvent) can be used to identify the individual compounds in each sample

## Key terms

- [paper chromatography](https://www.gradenine.co.uk/glossary/paper-chromatography)
- [formulation](https://www.gradenine.co.uk/glossary/formulation)

## Related

- [Revision notes for WJEC A-Level Chemistry (Wales)](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-manufacturer-produces-two-versions-of-6886c5e6) · Published by Druglandscape Ltd.