What are polar molecules and non-polar molecules? Give examples of both.

(N/A) $1$. Polar Molecules: $A$ molecule in which the center of positive charge and the center of negative charge do not coincide is called a polar molecule. These molecules possess a permanent electric dipole moment. Examples: $HCl$,$H_2O$,$NH_3$.
$2$. Non-polar Molecules: $A$ molecule in which the center of positive charge and the center of negative charge coincide is called a non-polar molecule. These molecules have zero permanent electric dipole moment. Examples: $O_2$,$H_2$,$CO_2$.