Which of the following has the lowest boiling point?

CONCEPT:

Boiling Points of Group 16 Hydrides

• The boiling point of a compound depends on the strength of the intermolecular forces.
• Hydrogen bonding significantly increases the boiling point of molecules like H₂O.
• In the absence of hydrogen bonding, the boiling point typically increases with molecular mass and polarizability.

EXPLANATION:

• H₂O forms strong hydrogen bonds, giving it the highest boiling point among these compounds.
• H₂S, H₂Se, and H₂Te exhibit weaker van der Waals forces since they do not form hydrogen bonds.
• Among H₂S, H₂Se, and H₂Te, the boiling point increases with molecular mass: H₂Te > H₂Se > H₂S.
• Therefore, H₂S has the lowest boiling point, as it has the smallest molecular mass and weakest intermolecular forces.

CONCLUSION:

The compound with the lowest boiling point is H₂S.