Which of the Following Pairs of Molecules Can Be Held

Question

Which of the following pairs of molecules can be held together by a hydrogen bond?
A) one polar molecule and one nonpolar molecule
B) two negative ions
C) two nonpolar molecules
D) two polar molecules

Accepted Answer

Hydrogen bonding occurs between a hydrogen atom bonded to an electronegative atom and a lone pair of electrons on another electronegative atom. Therefore, only polar molecules can participate in hydrogen bonding. Nonpolar molecules do not have electronegative atoms that can form hydrogen bonds. Negative ions do not have a partial positive charge on a hydrogen atom that can participate in hydrogen bonding. Therefore, the only possible pair of molecules that can form hydrogen bonds are two polar molecules.