Lily has a mixture of 4 compounds that they want to separate. All 4 compounds appear as white solid powders. When Lily adds 25 mL of chloroform (density = 1.492 g/mL; bp = 61C) to the mixture, everything dissolves with stirring. Lily decides to use acid-base extraction to separate the compounds from one another. Chloroform and water are immiscible, and all acids and bases will be prepared in water. 

 

First, Lily tries extracting the organic solution with 1.0 M HCl (20 mL). Which layer will be the organic layer in the separatory funnel?

a. the top layer

b. the bottom layer

c. there will only be one layer

 

What will be in the organic layer after the extraction with 1.0 M HCl?

nothing will be left in the organic layer

a. 1, 3, 4

b. 1, 2, 3, 4

c. 2 only

 

Lily sets the first aqueous layer aside and returns the organic layer to the separatory funnel. Next, they choose to extract with 0.50 M NaOH (20 mL). What will be left in the organic layer after this step?

a. 1, 3, 4, as salts

b. 2, 3

c. 2 only

d. 1, 3, 4

 

Lily dries the organic layer over anhydrous sodium sulfate and evaporates the chloroform using a rotary evaporator (rotovap). How does the rotovap  remove the solvent?

a. It does so by lowering the pressure acting on the solvent with a vacuum, which allows it to boil at a lower temperature

b. It lowers the temperature to freezing, which causes the solutes to precipitate out of any solvent

c. Rotovaps are not used to evaporate solvent

d. The rotation of the flask throws molecules of solvent into the air that can then be pulled into the collection trap

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