Final answer:
In pure ethanol, the strongest attractive interaction is hydrogen bonding, which is a strong type of dipole-dipole interaction involving hydrogen and oxygen atoms.
Step-by-step explanation:
The strongest attractive interaction in pure ethanol is hydrogen bonding. Hydrogen bonds are a type of dipole-dipole interaction that occurs when hydrogen is bonded to highly electronegative atoms like oxygen. In ethanol, the hydrogen atoms bonded to oxygen can form strong intermolecular attractions with oxygen atoms of neighboring ethanol molecules, leading to higher boiling points and unique properties compared to substances with only London dispersion forces or typical dipole–dipole interactions.