Two colorless liquids—acetone ( ) and glycerol ( )—are mixed in a beaker
CHEMISTRY · Multi-part · CBSE · Chemistry · Is Matter Around Us Pure? · Is Matter Around Us Pure?
Problem
Two colorless liquids—acetone (ρ=0.79gmL−1) and glycerol (ρ=1.26gmL−1)—are mixed in a beaker. A small amount of Sudan III, a nonpolar red dye that is insoluble in water but readily dissolves in hydrocarbon solvents, is added to the mixture. The beaker is stoppered, shaken, and left to stand. After several minutes, two visually distinct phases are observed.
(1) Part 1: (a) Identify which liquid (acetone or glycerol) constitutes the upper phase and which constitutes the lower phase. Support your answer with an analysis that considers both miscibility and density.
(2) Part 2: (b) Predict which phase will appear pink-red after the system reaches equilibrium. Explain how the molecular structure of Sudan III leads to the observed distribution of color.
(3) Part 3: (c) Suppose 15mL of water is gently poured down the inside wall of the beaker so that it forms a separate layer. Describe the final arrangement of layers you expect, including their relative positions and whether each will contain any visible coloration.