A-Level Pre-Lab Video for Using a Separating Funnel

Clamp the separating funnel around the ground glass joint at the top before transferring any liquids. Ensure the stopcock is closed (tap horizontal) and fill the funnel no more than 2/3 full using a measuring cylinder or long-stemmed funnel to prevent spillages.

Pour both the solution and extraction solvent into the funnel. Aqueous and organic phases will form separate layers based on their densities, with the denser solution settling to the bottom.

Remove the funnel from the clamp and invert it upside down with both hands. Open the tap to release pressure, then repeat 2-3 inversions followed by opening the tap to release pressure again, repeating this cycle 5-10 times total for maximum mixing.

Reattach the separating funnel to the clamp and watch as the organic and aqueous layers begin to separate. The dye will migrate into the organic phase, clarifying which layer is which.

Remove the stopper from the top of the funnel and open the tap to drain the bottom layer into a clean conical flask. Slow the flow rate as the layer drains and close the tap when the separation between layers is no longer visible.

Pour the remaining top layer from the funnel into a new clean conical flask. Set aside the first flask containing the bottom layer.

Pour fresh extraction solvent from a measuring cylinder into a conical flask containing the desired layer (organic or aqueous), then repeat the inversion mixing and layer separation process. Collect the target layer into a new clean conical flask after each separation to maximize yield.

After three total extraction cycles, you will have a conical flask containing purified solution with your final product. This solution often requires additional purification by distillation or recrystallization to remove remaining impurities.