Chemistry Distillation ...

[MCAT guy]

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I was doing a BR passage and missed this question. Can anyone explain the difference between B and C, they seem like similar answers and I don't get the difference... B was correct and I answered C.

An alternative to freeze-drying procedure that would still yield dehydrated coffee is which of the following?

B. Distillation of the water to collect the residue
C. Distillation and collection of the solvent

(The goal is attempting to separate water and impurities from coffee, the passage used a sublimation process to get rid of water and impurities. I thought that the distillation of the solvent would be removing the water, leaving the coffee behind, but the answer B is superior?).

 

[lorenzomicron]

collection of the solvent is collecting the water.

collecting the residue is collecting the coffee.

 

[MCAT4life]

the water would have lower BP than the solute therefore it distills out first. Leaving behind the coffee as the residue left in the (container).
If you are collecting the solvent, which is the water, you would just have very pure water, with negligible amounts of coffee, if any.