Question

Using your knowledge of intermolecular forces, explain why 2-propanol is used to extract the fat from a potato chip.

Answer 1

Fat are relatively non-polar molecules, so they can be extracted out from a system using relatively non-polar solvents. However, most of the plant cells (e.g. potato in this case) membranes are made of molecules that have both polar and non-polar areas. The polar heads of these molecules will stick outwards and non-polar tails inwards making it difficult for non-polar solvents to interact with the non-poplar tails and extract them. As these molecules has some part which is polar and has some part which is non-polar in nature, we basically require a solvent that shows similar characteristics. Therefore, a mixture of isopropanol and hexane is used. Isopropanol is polar enough to interact with the polar regions and help pull apart the cell membrane while also being non-polar enough to help in extracting non-polar fats and being soluble in the hexane.