Importance of Polarity of Water

What are the consequences of molecular polarity of water on its nature and properties? This polarity has a large impact on the properties of water. Here are some of the properties of water that can be attributed to its polar nature.

Hydrogen Bonding

Due to the polar nature of water, a special kind of bonding occurs between every molecule of water and its surrounding molecules. The negatively charged oxygen atom attracts surrounding hydrogen atoms of other water molecules, which are positively charged, creating a weak bond called the 'Hydrogen Bond'. This hydrogen bonding is responsible for most of the peculiar properties of water.

High Specific Heat & Heat of Vaporization

Specific heat is the amount of heat absorbed by one gram of a substance to raise its temperature by 1 degree Celsius. Heat of vaporization is the heat absorbed by a substance to transform from liquid to gaseous state. Water has a high specific heat and higher heat of vaporization than most substances due to hydrogen bonding. These two properties endow the water molecules with an ability to buffer large temperature fluctuations and regulate the climate on Earth.

Cohesion & Adhesion

The hydrogen bonding between molecules makes water more 'sticky' leading to a higher degree of cohesion and adhesion. Adhesion and cohesion are important properties of water which play a big role in its biological functions.

Higher Surface Tension

A higher surface tension of water endows it with the property of capillary action, which helps it rise against gravity through tubes and veins of plants to reach greater heights.

Ice Floats on Water

Due to the hydrogen bonding, which is a consequence of the polarity of water, ice is less dense than water causing it to float. This has important consequences for marine life as it gets protected in winter by the insulating sheet of ice that floats above water, while keeping underlying layers warm.

Water As Solvent of Life

The polarity of water molecule makes it a universal solvent. It can dissolve salts, acids, sugars, as well as alkalis and gases. Most cell components including proteins, polysaccharides and DNA dissolve in water making it the basis of life.