Final answer:
The strongest hydrogen bond listed would be between H2O and HF because the bond involves fluorine, which is the most electronegative element, making the attraction stronger than with nitrogen or oxygen.
Step-by-step explanation:
The hydrogen bond occurring between two molecules that would be the strongest is option D, between H2O and HF. This is due to the hydrogen bond being particularly strong when it involves a hydrogen atom that is attached to a highly electronegative atom such as fluorine (in HF), which has a higher electronegativity than oxygen (in H2O) or nitrogen (in NH3).
Hydrogen bonding occurs when a hydrogen atom bonded to an electronegative atom such as nitrogen, oxygen, or fluorine experiences an electrostatic attraction to a lone pair of electrons on a neighboring electronegative atom. Since fluorine is the most electronegative element, the hydrogen bond formed with HF is generally the strongest among the ones listed.
While both NH3 and H2O can form hydrogen bonds, the bond strength is less than that between H2O and HF. Even though water molecules can form up to four hydrogen bonds, the individual bond strength is less compared to the hydrogen bond in HF. Furthermore, hydrogen bonding in ammonia occurs between nitrogen and hydrogen, and hydrogen bonding in acetic acid is between oxygen and hydrogen; however, these would not be as strong as the bond between H2O and HF.