Give examples of polar and non-polar molecules.

(N/A) polar molecule is one in which the centers of positive and negative charges are separated even in the absence of an external electric field. These molecules possess a permanent electric dipole moment. Examples include $H_2O$,$HCl$,$NH_3$,and $CO$.
$A$ non-polar molecule is one in which the centers of positive and negative charges coincide. These molecules do not possess a permanent electric dipole moment. Examples include $H_2$,$O_2$,$N_2$,and $CO_2$.