Four separate food dyes (C, D, E and F) and a mixture of food dyes (X) were investigated using paper chromatography. The diagram shows the apparatus used.
(a) Why should the water level be below the food dyes?
Correct answer
to stop the dyes from dissolving into water
📝 Detailed explanation
Keeping the water below the dyes allows the solvent to travel up the paper by capillary action, carrying the dissolved dyes with it gradually. This enables separation based on how strongly each dye is attracted to:the solvent (mobile phase)
the paper (stationary phase)