Question Constellation Sign up for free AQA · GCSE · Chemistry · Higher
Red dye movement in chromatography
Printer ink is a mixture of chemicals.
A student used chromatography to investigate the colours in a printer ink. The student put a spot of the printer ink on the start line.
Figure 4 shows the results.
Explain why the red colour did not move from the start line.
Write your answer first. You can study the marking guidance whenever you need it.
Study the marking See what earns credit and compare it with a full-mark answer.
Marking points
- 1 States that the red colour is insoluble in the solvent.
- 2 Links insolubility to the red colour not moving with the solvent.
Full-mark answer
The red colour is insoluble in the solvent, so it does not dissolve and move up the paper with the solvent.
Why this answer loses marks
The red dye was too heavy to move.
Mass is not the credited explanation; link insolubility in the solvent to the dye not being carried.