The solvent diethyl ether can be mixed with water but only by shaking the two liquids together. After the shaking is stopped, the liquids separate into two layers, much like oil and vinegar. The free-base form of the alkaloid caffeine is readily soluble in diethyl ether but not in water. Suggest what might happen to the caffeine of a caffeinated beverage if the beverage was first made alkaline with sodium hydroxide and then shaken with some diethyl ether.

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Quizplus · Accepted Answer

When the beverage is first made alkaline with sodium hydroxide, it transforms the acidic caffeine molecules into their alkaline free base form. This form of caffeine is readily soluble in diethyl ether but not in water. Shaking the mixture with diethyl ether would allow the caffeine to transfer from the aqueous layer to the solvent layer, resulting in increased caffeine extraction. The color change of the water layer is not relevant to the solubility of caffeine in ether. The formation of the free acid is unlikely in this scenario, and the two liquids would still separate into two layers after shaking.

The Solvent Diethyl Ether Can Be Mixed with Water but Only