Worksheet: Liquid–Liquid Separation
In this worksheet, we will practice describing the use of separatory funnels for washing and extraction methods, assessing hazards and common errors.
Which of the following pieces of apparatus is not typically used when separating liquids?
- BSeparating funnel
- DRetort stand
- EPasteur pipette
When extracting a solute from an organic solvent into water, which of the following steps is not required?
- AThe stopper is removed from the separating funnel.
- BThe separating funnel is inverted and shaken repeatedly.
- CThe aqueous solution is returned to the separating funnel.
- DWater or brine are added to the separating funnel.
- EThe mixed liquids are left to stand until separation takes place.
After washing a reaction mixture, an emulsion is observed instead of separate aqueous and organic layers. Which of the following actions would not improve the separation?
- AStir the mixture.
- BRemove the stopper from the funnel.
- CAdd salt.
- DCentrifuge the mixture.
After adding a liquid mixture to a separating funnel and inserting a stopper, in which order should the following actions be performed?
- Shake or swirl the funnel.
- Vent the funnel.
- Invert the funnel.
- A3, 2, 1
- B3, 1, 2
- C1, 3, 2
- D2, 3, 1
- E1, 2, 3
A student is extracting a solute into a nonhalogenated organic solvent using a separating funnel. After inverting and shaking the flask, the apparatus appears as shown.
What must the student do before dispensing liquid from the separating funnel?
- AAdd a stir bar to the Erlenmeyer flask and place it on a hotplate
- BAdd an indicator to the funnel to highlight the liquid–liquid interface
- CClamp the Erlenmeyer flask
- DRemove the stopper from the funnel
- EInvert and shake the flask again
A large amount of solute remains in the aqueous layer. After dispensing the bottom layer from the funnel, what must the student do?
- ALeave the top layer in the funnel, add pure organic solvent, and repeat the extraction
- BLeave the top layer in the funnel, add distilled water, and repeat the extraction
- CReturn the bottom layer to the funnel, add pure organic solvent, and repeat the extraction
- DDispense the top layer into another flask, return the bottom layer to the funnel, add distilled water, and repeat the extraction
- EDispense the top layer into another flask, return the bottom layer to the funnel, add pure organic solvent, and repeat the extraction