O Water is denser than isopropanol, so the water layer will always be below the isopropanol layer if they are both in the same container. What does this tell you about the make-up of the pigments for each specimen?

One is polar and the other is non-polar.

Explanation:

The makeup of both water and isopropanol is different from each other due to their polar nature. Water is a polar substance means that it makes poles i.e. positive or negative while on the other hand, isopropanol is non-polar substance so due to this reason water and isopropanol make different layers. If both are polar or nonpolar substances so they will able to mix with each other.