What makes hydrogen bond?
Do you mean like hydrogen bonding in water molecules and DNA? Basically on certain molecules, most notably Oxygen, we find a partial negative. This is because Oxygen is generally more electronegative than what it bonds with(like carbon) so it holds the electrons closer (so we say). Then, Hydrogen is usually less electronegative (anything more electronegative than say boron) than what it bonds with so it has a partial positive. Therefore, with these partials there’s slight bonding between Hydrogens and other molecules (they are on the outside of the molecule and offer little strain for intermolecular bonding) like Oxygen. It’s not a “real” bond per say, but it offers “slight electron” sharing so that hydrogens and what it slightly bonds with are all more stable. Therefore, like in an a very polar molecule like H20 we find great stability as there’s a huge hydrogen bonding network that neutralizes all the partial charges. If you don’t understand “partial charges” please read about polari
