Let us understand the concept of polar and non-polar solvents.
Polar solvent is a type of solvent that has large partial charges or dipole moments. The bonds between the atoms have very different but measurable electronegativities. A polar solvent can dissolve ions and other polar compounds.
It is possible because of the electrical charges pulling on different parts of the solute molecules. The positively charged ions of the solid compound are attracted by the negatively charged side of a solvent molecule and vice versa. This enables the polar compound to be soluble in the polar solvent. Due to this activity, the ions are evenly distributed throughout the solvent. As for the polarity of the solvent, it basically emerges due to the existing bonds of the atoms with different electronegativity values that leads to the formation of the molecule.
Water is a popular example of a polar solvent. What makes it a polar solvent? If we look at the molecules of water it has a unique structure with two hydrogen bonds. Further, there is a large difference in the electronegativity between the hydrogen and oxygen atoms. As such, the large oxygen attracts the electrons close together and gets negatively charged. The hydrogen atoms each get a smaller share of the shared electrons and thus gains a positive charge. This is the very reason for water becoming a very strong dipole molecule.
Also Read: Hydrogen Bonding
Non-polar solvents are liquids or solvents that do not have a dipole moment. As a result of this, the solvents are missing any partial positive or negative charges. Basically, they have small differences in electronegativity. We can also say that the bonds between atoms come with similar electronegativities. Non-polar solvents cannot dissolve polar compounds since no opposite charges exist and the polar compound is not attracted. It is this absence of partial charge that also makes these molecules “non-polar”.
Some of the examples of non-polar solvents include hexane, pentane, toluene, benzene, etc.