But first let us define "polarity", and this represents charge separation. In the H-Cl molecule, chlorine is more electronegative than hydrogen, and STRONGLY polarizes electron density towards itself. And given this result, we could represent the dipole as stackrel(""^+delta)H-stackrel(delta^-)Cl..hydrogen chloride is thus a strongly polar molecule, and this polarity tends to elevate the boiling point of the molecule via intermolecular hydrogen-bonding.
On the other hand, in an HOMONUCLEAR diatomic molecule, e.g. H_2, Li_2, C_2, N_2, O_2, F_2...there CAN BE NO QUESTION of "polarity", of charge separation, in that the participating atoms in the molecule have the SAME electronegativity, and thus electron density is SHARED EQUALLY by the two atoms that participate in the bond....
You happy with this....?
