Water is a liquid at room temperature due to its unique molecular structure and the properties of hydrogen bonding. Hydrogen bonding is the intermolecular force that occurs when a hydrogen atom in a molecule is covalently bonded to a highly electronegative atom, such as oxygen or nitrogen. In the case of water, hydrogen bonding occurs between the hydrogen atoms of one water molecule and the oxygen atom of another water molecule.

This hydrogen bonding creates a strong attraction between water molecules, which holds them together and prevents them from moving freely past each other. As a result, water has a relatively high boiling point and a low freezing point compared to other substances of similar molecular weight. At room temperature, these hydrogen bonds are still strong enough to keep the water molecules together in a liquid state.

The unique properties of water, including its surface tension, cohesion, and high specific heat capacity, are also influenced by hydrogen bonding. These properties are essential for the survival of many organisms and play a crucial role in various biological processes.