Separation of Solution & Mixtures Chromatography (College Board AP Chemistry)

A student investigates various dyes using paper The student has samples of three pure dyes, labeled A , B , and C , and an unknown sample that contains one of the three dyes. The student prepares the chromatography chambers shown above on the left by putting a drop of each dye at the indicated position on the chromatography paper (a polar material) and standing the paper in a nonpolar solvent. The developed chromatograms are shown above on the right.

Which dye (A, B, or C) is the least polar? Justify your answer in terms of the interactions between the dyes and the solvent or between the dyes and the paper.

Which dye is present in the unknown sample? Justify your answer.