Final answer:
The strongest hydrogen bond would occur between water (H₂O) and hydrogen fluoride (HF) due to the high electronegativity of oxygen and fluorine, and HF's ability to participate in hydrogen bonding with water's lone pairs on oxygen. The correct answer is O H₂O and HF.
Step-by-step explanation:
The hydrogen bond that would be the strongest among the given options is the one occurring between H2O (water) and HF (hydrogen fluoride).
This is because hydrogen bonds are especially strong dipole-dipole interactions between molecules that have hydrogen bonded to a highly electronegative atom, such as O, N, or F.
In water, hydrogen is bonded to oxygen, which is highly electronegative, and in hydrogen fluoride, hydrogen is bonded to fluorine, which is even more electronegative than oxygen.
The combination of these two molecules results in the strongest hydrogen bonding due to the high electronegativity of the atoms involved and the ability of HF to participate in hydrogen bonding with the lone pair of water's oxygen.