Question

Is Sodium chloride a polar or nonpolar molecule?

Answer 1

The chemical formula of sodium chloride is $NaCl$ .Polarity is an inherent characteristic of covalent compounds and is theoretically not applicable to ionic compounds however the separation of charges in ionic compounds causes them to behave like polar molecules.

Complete answer:
The atoms of elements always seek to attain stability.They do this by forming chemical bonds with atoms of the same or different elements.In order to form chemical bonds atoms need to donate,accept or share electrons.When molecules are formed atoms with difference in electronegativities also bond together. This difference in electronegativity causes a change in distribution of electron density since electrons tend to shift towards atoms with greater electronegativity,the result is a formation of polarity which is quite similar to an electric dipole.The molecules which exhibit polarity are known as polar molecules and the ones which don’t exhibit are known as non-polar molecules.
Let us consider a Sodium chloride molecule which is chemically represented by $NaCl$ this represents a 1:1 ratio of sodium and chloride ions .It is commonly known as salt and it’s an essential component used by our body for various biological process such as absorption,transportation.
In sodium chloride,the atoms sodium and chloride are bonded to each other with ionic bonds.Due to the large difference in electronegativity of Sodium ( $Na +$ ) and Chloride ( $Cl -$ ) ions,therefore sodium chloride which is an ionic compound behaves like a polar molecule.

Note:
It is often said that ionic compounds are not electrical dipoles since they consist of separate positive and negative charge.However due to this separation of charges they tend to act like polar molecules.