Those substances with a majority of non-polar bonds and are insoluble in water are called as hydrophobic molecules. This property is true especially in case of hydrocarbons that have C-H bonds. As water molecules are not attracted to these substances they do not surround them and do not form a solution.
Due to the polar property of water, two adjacent water molecules form a linkage. This linkage is called the hydrogen bond that has 1/20th strength of a covalent bond. Thus, hydrogen bonds are strongest when there are three atoms present in a straight line.
Biological Properties of Water
There are some biological properties of water that makes it so precious. There are many living organisms that live in water like microscopic organisms. These include bacteria, viruses, fungi, protozoans, phytoplankton, zoo plankton, insects, worms, plants and fish. The neutral pH of water makes it life sustainable. Water makes up 60% of a cell and is vital for survival of life. More than 70% of earth's surface is covered with water. It is largely found in oceans and other large water bodies. Water is continuously recycled through the process of evaporation and transpiration, precipitation, run off, etc. Clean drinking water is very important for humans as well as other animals as well as plants.
Unique Properties of Water
- Water has highest surface tension compared to all liquids, except mercury.
- Water expands on freezing, this is one of the unique properties of water that is seen in very few other substances.
- Water will expand with temperature increase above 4º C.
- Water has the highest latent heat of fusion and vaporization.
- Water is slightly compressible as density of water is high.
- Water is an universal solvent.
- Water is one of the few inorganic liquid substances.