Final answer:
The boiling point of a substance is influenced by its intermolecular forces, with hydrogen bonding playing a significant role for molecules like H₂Se and H₂O. Water (H₂O) has a higher boiling point than hydrogen selenide (H₂Se) due to oxygen's greater electronegativity, which allows stronger hydrogen bonding. Therefore, the substance with greater electronegativity, which is Option 2, has a higher boiling point.
Step-by-step explanation:
When comparing the boiling points of H₂Se (hydrogen selenide) and H₂O (water), we need to consider several aspects of intermolecular forces and molecular properties that influence boiling points. These include molecular weight, electronegativity, and the presence of hydrogen bonds. Hydrogen bonding is a strong intermolecular force that significantly increases the boiling point of a molecule. While both H₂Se and H₂O have hydrogen atoms bonded to an electronegative atom, the key difference is the ability of water to form stronger hydrogen bonds due to oxygen's higher electronegativity compared to selenium.
In the given options, higher molecular weight is correlated with higher boiling points in nonpolar molecules where London dispersion forces dominate. However, in polar molecules with hydrogen bonding, like water, this is not the primary factor affecting the boiling point. The presence of a highly electronegative atom like oxygen in H₂O allows for stronger hydrogen bonds, resulting in a much higher boiling point for water than would be predicted solely based on its molar mass.
Therefore, when comparing H₂Se and H₂O, the substance with the higher molecular weight will not necessarily have a higher boiling point. Instead, the correct option for the substance with a higher boiling point is Option 2: Greater electronegativity. Water (H₂O), with its greater electronegativity due to the presence of oxygen, exhibits stronger hydrogen bonding and thus has a higher boiling point than hydrogen selenide (H₂Se).