What is one property of water that allows solid water (ice) to float on liquid water? A) ability to act as a universal solvent B) high specific heat capacity C) ability to be most dense in liquid form D) ability to change to a gas below its boiling point

What this question is really asking

Ice floats only if the solid phase is less dense than the liquid phase. So we need the option that describes water’s unusual density behavior.

Picking the correct option

C is correct because water is most dense in liquid form, and its density decreases when it freezes.

Why freezing makes water less dense

When water freezes, hydrogen bonds lock molecules into a more open lattice. That structure takes up more volume for the same mass, so density drops:

$$\rho = \frac{m}{V}$$

If $m$ stays the same and $V$ increases, then $\rho$ decreases. Lower density ice floats on higher density liquid water.

Why the other choices do not explain floating

• A (universal solvent) explains dissolving ability, not density.
• B (high specific heat) explains temperature buffering, not floating.
• D (evaporation below boiling point) is about phase change to gas, not solid vs. liquid density.