A chemist compares a textile dye solution with four reference dyes. Spots of the textile dye solution and of each reference dye are put on the same pencil start line of one piece of chromatography paper. The paper is then stood in a beaker of solvent.
| Substance | Rf values of spots |
|---|---|
| Textile dye solution | 0.29 and 0.72 |
| Dye P | 0.16 |
| Dye Q | 0.29 |
| Dye R | 0.72 |
| Dye S | 0.86 |
Which reference dye matches the spot from the textile dye solution that travelled furthest?
Dye R
Dye S
Dye Q
Dye P
102 exam-style questions on OCR GCSE Chemistry 2.1 Purity and separating mixtures, covering 2.1.1 Pure substances and melting point data, 2.1.2 Relative formula mass and empirical formula, 2.1.3 Formulations as useful mixtures, 2.1.4 Techniques for separating mixtures, and 2.1.5 Chromatography and Rf values. Each one has a worked solution and a mark scheme showing where the marks go.