Which of the following has the highest boiling point?

Correct option is A

The correct answer is (a) H2O

Explanation:
• Water (H2O) possesses the highest boiling point among all group 16 hydrides (H2O, H2S, H2Se, H2Te) due to the presence of extensive intermolecular hydrogen bonding.
• The high electronegativity of oxygen compared to sulfur, selenium, and tellurium leads to strong dipole-dipole attractions (hydrogen bonds) that require significant thermal energy to break.

Information Booster:
• The boiling point trend for the rest of the group increases as molecular mass increases: H2S < H2Se < H2Te.
• H2O is an anomalous outlier; without hydrogen bonding, water would be a gas at standard room temperature.

Additional Knowledge:
H2S (Option b)
• Hydrogen sulfide exhibits very weak dipole interactions and no hydrogen bonding, resulting in a boiling point of roughly -60°C.
H2Se (Option c)
• Heavier than H2S but still lacks hydrogen bonding; boiling point is higher than H2S but vastly lower than H2O.
H2Te (Option d)
• Has the strongest Van der Waals dispersion forces among the last three due to highest molecular weight, yet still falls far short of water's boiling point.
None of the above/More than one of the above (Option e)
• Incorrect, as H2O distinctly holds the highest value.

So the correct answer is (a)