Concept:Ethanol molecules are held together by more than one type of intermolecular force.
Explanation:Ethanol,
C2H5OH, has an
−OH group. The hydrogen atom of this group forms hydrogen bonds with the oxygen atom of a neighbouring ethanol molecule.
Hydrogen bonding is a strong dipole-dipole attraction and is the main intermolecular force in ethanol.
But ethanol also has an ethyl group,
−C2H5. This nonpolar part gives rise to weak temporary dipoles. These produce London dispersion forces, which are included in Van der Waals forces.
So, between adjacent ethanol molecules, both hydrogen bonding and Van der Waals forces are present. These are attractions between molecules, not covalent bonds inside the molecule.
Answer:C. hydrogen bonding and Van der Waal's forces