Question

In most compounds, the solid phase is denser than the liquid phase. Why isn’t this true for water?

Short answer

The molecules are placed farther apart, which leads to a lesser density of the ice.

Step-by-step solution

Define Phase change

A phase change is when matter changes from one state (solid, liquid, gas, plasma) to another.

Explanation of why it is not true for water?

The solid phase of water is known to be ice. The structure of ice has a more fixed structure in comparison to water. It is so because the ice structure exists as a crystal lattice solid.

Solids have a more solid and compact structure in comparison to liquids. So, as it is a 3d crystal lattice that is an open structure, it is more dispersed than a liquid's structure.

As the molecules are placed very far, this leads to a lesser density of ice.

Therefore, molecules are placed far from each other, leading to a lesser ice density.