1. Freezing water: The number of hydrogen bonds increase.
2. Heating water: Hydrogen bonds break
Explanation:
In the liquid state, hydrogen bonds are continuously formed and broken and the average amount is 3.4. During freezing, molecule's energy decreases and there is less energy to break hydrogen bonds and for this reason, these bonds are more stable and average hydrogend bonds are close to 4 bonds.
When liquid water is heated, the kinetic energy raises and it causes the hydrogen bonds to break.
