A laboratory mixture consists of three components: coarse sea salt crystals (insoluble in ethanol), liquid ethanol, and blue food dye fully dissolved in water. The ethanol and the dye-containing water are miscible with each other. A student must recover (1) dry sea salt, (2) pure ethanol, and (3) an aqueous solution that still contains all of the blue dye. Assume no appreciable loss of ethanol to evaporation can be tolerated.
Design and justify a separation plan that meets the recovery goals listed above.
(a) Identify the physical property that allows the first separation step you select. Describe the apparatus you would use and explain how that apparatus exploits the identified property.
(b) After completing the first step, you now have a two-component liquid mixture. Propose a method to separate these two liquids so that the ethanol is collected with at least 95 % purity by mass. Explain how an intermolecular-force difference leads to the success of this step.
(c) For each of the two steps you proposed, describe one procedural detail that minimizes product loss or contamination.
(d) Summarize the final order of operations in your overall scheme. Justify why reversing the order of the two steps would fail to achieve the stated recovery goals.