Place one hand near the stopcock and one hand firmly over the stopper, and invert the funnel. Open the stopcock to vent any built-up pressure. Close the stopcock, vigorously swirl the liquid for a few seconds, then vent the pressure again. Continue to swirl the solution for several minutes, and be certain to vent the pressure frequently.
The two liquids have been thoroughly mixed when venting the solution no longer produces the hiss of escaping gas. Then place the separatory funnel back into the ring stand and immediately remove the stopper.
When the liquids have separated into two distinct phases, the bottom liquid
may be drained from the separatory funnel.
Why should the stopper be removed once you have returned the separatory funnel to the ringstand?
Answer
Pressure could build up in the flask and eject the stopper. Also, the liquid will not drain effectively with the stopper in place. See video clip.
Why should the stopper be removed once you have returned the separatory funnel to the ringstand?