Concept:Water is unique because it expands when it freezes, making the solid form less dense than the liquid form.
Explanation:Most liquids contract when they freeze, so their solids are denser than their liquids.
Water behaves differently because of hydrogen bonding.
As water freezes, its molecules arrange into an open hexagonal structure.
This arrangement creates more space between molecules, so the volume increases.
Therefore, ice is less dense than liquid water:
ρice<ρliquid water.
Because ice is less dense, it floats on water.
This expansion on freezing is a characteristic property of water.
The other options are not true: water is a good solvent, it can evaporate, and it has a high heat capacity.
Answer:C. It expands when freezing.