Step 1: Nature of intermolecular forces.
- In , due to the high electronegativity of oxygen, strong intermolecular hydrogen bonding is present.
- In , sulphur is less electronegative, and hence hydrogen bonding is absent. Only weak van der Waals forces are present.
Step 2: Effect of intermolecular forces.
- Strong hydrogen bonding in holds the molecules together, giving it a liquid state at room temperature.
- Weak forces in cannot hold molecules strongly, so it exists as a gas at room temperature.
Conclusion:
is liquid due to strong hydrogen bonding, while is gas due to weak van der Waals forces.