MediumChemistryHigh School (9–10)GeneralMixtures and Solutions › Separation of MixturesNumericalConceptual
Three known dyes have these Rf values in a solvent: dye A 0.25, dye B 0.48, dye C 0.82.
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
Three known dyes have these values in a solvent: dye A , dye B , dye C . An ink from a forged letter is run in the same solvent. The solvent rises , and the ink gives two spots, at and . Which dyes are in the ink?
Need a reminder? The key ideaShow
In chromatography, each dye is carried up the paper at its own speed. , measured from the starting line. It has no unit, lies between and , and identifies a substance in a given solvent.
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. The lower spot. : dye B.
Step 2. The upper spot. : dye C.
Answer: The ink is a mixture of dyes B and C. It has no dye A.
Check. The comparison is fair only because the ink and the known dyes were run in the same solvent.
Discussion (0)
Log in to join the discussion.
Loading…