Question

What intermolecular interactions will exist between molecules in a mixture of ethanol and acetone in solution?

Select all possible answers

-Hydrogen bonding

-dipole-dipole interactions

-dispersion (van der Waal) interactions

-No intermolecular interactions between these molecules.

Answer 1

Ethenol has hydroxyl group with oxygen and hydrogen. Oxygen being electronegative atom it attracts shared (bond) electrons towards it self and make O-H bond polar keeoing delta positive charge on hydrogen and detla negative charge on oxygen. In acetone, there is a polar C=O bond. Which makes delta positive charge on carbon and delta negative charge on oxygen. Thus the delta positive charged proton will form hydrogen bond with delta negative chrages (or the loan pair of electrons on the carbonyl oxygen). Thus the solution will have hydrogen bonding present between these to molecules.

As said earlier, both molecules are polar molecules and hence both will exert dipole-dipole interaction.

"Some intermolecular interactions that cannot be summerised as regular electrostatic attractions, these are called as dispersion forces. These forces arises due to temporary attraction resulted when electrons in two adjacent atoms occupy position to make atoms form temparary dipoles" And these are always present in the polar molecules but there magnetuted is so low that it cannot be compared with othere strong molecular forces.

Thuse the given solution, will have all of these forces:

-Hydrogen bonding

-dipole-dipole interactions

-dispersion (van der Waal) interactions.