A researcher uses paper chromatography to separate coloured substances in an extract from tree leaves. Several applications of the extract are needed at the same position on the pencil origin line.
Why should each application be allowed to dry before the next application?
The pencil origin line is prevented from dissolving in the rising solvent
The extract is prevented from washing off the paper into the solvent
The coloured substances are made more soluble in the solvent
More extract can be added without making the starting spot wider
113 exam-style questions on AQA GCSE Chemistry 8.1 Purity, formulations and chromatography, covering 8.1.1 Pure substances, 8.1.2 Formulations, and 8.1.3 Chromatography. Each one has a worked solution and a mark scheme showing where the marks go.