Which property of water is responsible for ice floating on liquid water?

• A. Water molecules are more tightly packed in the solid state.
• B. Water expands and becomes less dense when it freezes.
• C. Water is a universal solvent.
• D. Water has a high specific heat capacity.

Answer: (B)

Verified step by step guidance

1. Understand the problem: The question is asking which property of water explains why ice floats on liquid water. This involves understanding the physical and chemical properties of water in its solid and liquid states.
2. Recall the concept of density: Density is defined as mass per unit volume. When a substance becomes less dense, it means its molecules are spread out over a larger volume.
3. Examine the behavior of water when it freezes: Unlike most substances, water expands when it freezes due to the formation of a crystalline structure held together by hydrogen bonds. This structure causes the molecules to be spaced farther apart compared to the liquid state.
4. Relate density to floating: Since ice is less dense than liquid water, it will float. This is a direct result of the expansion and reduced density of water in its solid state.
5. Eliminate incorrect options: The other choices (water as a universal solvent, high specific heat capacity, and tightly packed molecules in the solid state) do not explain the phenomenon of ice floating. The correct property is water's expansion and reduced density upon freezing.