What is the attraction between water molecules called?
The attraction between water molecules is known as hydrogen bonding. This unique intermolecular force plays a crucial role in the properties and behavior of water, making it one of the most fascinating substances on Earth. Hydrogen bonding is responsible for many of water’s unique characteristics, such as its high boiling point, high surface tension, and ability to dissolve various substances.
Hydrogen bonding occurs when a hydrogen atom in one water molecule is attracted to the oxygen atom in another water molecule. This attraction arises due to the difference in electronegativity between oxygen and hydrogen. Oxygen is more electronegative than hydrogen, meaning it has a stronger pull on the shared electrons in the covalent bond between the two atoms. As a result, the oxygen atom becomes slightly negative, while the hydrogen atom becomes slightly positive. This creates a dipole, with the oxygen atom having a partial negative charge and the hydrogen atom having a partial positive charge.
The partial negative charge on the oxygen atom of one water molecule is attracted to the partial positive charge on the hydrogen atom of another water molecule, forming a hydrogen bond. These hydrogen bonds are relatively weak compared to covalent or ionic bonds, but they are strong enough to significantly influence the properties of water.
One of the most notable effects of hydrogen bonding is water’s high boiling point. In order for water to boil, the hydrogen bonds between its molecules must be broken. This requires a significant amount of energy, which is why water has a much higher boiling point (100 degrees Celsius) compared to other molecules of similar size, such as hydrogen fluoride (HF) or hydrogen chloride (HCl), which have similar electronegativity differences but weaker hydrogen bonding.
Hydrogen bonding also contributes to water’s high surface tension. The hydrogen bonds between water molecules create a cohesive force that resists the tendency of the water to spread out or flatten. This is why water forms droplets and maintains a spherical shape, rather than spreading out as a flat layer.
Furthermore, the ability of water to dissolve various substances is largely due to hydrogen bonding. When a solute is added to water, the hydrogen bonds between water molecules can be broken and reformed with the solute molecules. This allows water to dissolve a wide range of substances, including ionic compounds, polar molecules, and some non-polar molecules.
In summary, the attraction between water molecules, known as hydrogen bonding, is a vital force that shapes the unique properties and behavior of water. Its strength and influence on water’s boiling point, surface tension, and solubility make hydrogen bonding a crucial aspect of life on Earth.
