Question

ap
unit 3 practice #2
15.
based on the results of the paper chromatography experiment shown above, which of the following can be concluded about the dye?
(a) it has a small molar mass.
(b) it has weak intermolecular forces.
(c) it has a weaker attraction for the stationary phase that it has for the mobile phase.
(d) it has a stronger attraction for the stationary phase than it has for the mobile phase.

Explanation:

In paper chromatography, the mobile phase is the solvent and the stationary phase is the chromatography paper. If a dye has a weaker attraction for the stationary phase (paper) than for the mobile phase (solvent), it will move further up the paper. In the given diagram, the dye has moved away from its original position towards the solvent front, indicating that it is more attracted to the mobile phase (solvent) than to the stationary phase (paper).

• Option A: Molar mass is not directly related to the movement in paper chromatography shown in this basic setup. The movement is more about intermolecular forces between the dye - stationary phase and dye - mobile phase.
• Option B: Just having weak intermolecular forces in general is too vague. We need to compare the forces with the stationary and mobile phases.
• Option C: Since the dye has moved up the paper (towards the solvent front), it has a weaker attraction for the stationary phase (paper) compared to its attraction for the mobile phase (solvent).
• Option D: If it had a stronger attraction for the stationary phase, it would not have moved as far up the paper.

Answer:

C. It has a weaker attraction for the stationary phase that it has for the mobile phase.