Cl is an electronegative element and hydrogen is electropositive. Why are intermolecular interactions involving H and Cl not considered as H bonding? I read it in a book but there was no reason given for it.
As per my teacher, the reason we say that Chlorine does not form hydrogen bonds, even though its electronegativity is almost same as N (both have electronegativity values around 3.0 as per the Pauling Scale) is because :
Chlorine being a third period element, has a relatively larger size as compared with Nitrogen and Oxygen, so it has a quite large and more diffused electron cloud. Therefore the dipole-dipole interactions in HCl are not as strong as the ones encountered in HF and H₂O, and so it wouldnt be quite accurate for them to be called as Hydrogen Bonds, as the ones in HF and H₂O are much stronger.
Hope this answered your question.