Concept:The physical state of a substance at ordinary temperature depends on the strength of its intermolecular forces.
Explanation:In water,
H2O, oxygen is highly electronegative.
Hydrogen atoms form strong hydrogen bonds with oxygen atoms of neighbouring molecules.
These strong hydrogen bonds hold water molecules tightly together, making
H2O a liquid at room temperature.
In hydrogen sulphide,
H2S, sulphur is less electronegative than oxygen.
Therefore,
H2S cannot form strong hydrogen bonds.
Only weak dipole-dipole or London forces exist between
H2S molecules.
These weak forces allow
H2S to escape easily as a gas at ordinary temperature.
Hence, the correct reason is the presence of strong hydrogen bonds in water.
Answer:The correct option is B: strong hydrogen bonds holding its molecules together.