why is hydrogen bonding only possible with hydrogen?
Have you checked wikipedia to get a basic idea of what a hydrogen bond is?
See your other post below.
Hydrogen bonding is a special type of intermolecular force that occurs between a hydrogen atom bonded to a highly electronegative atom (such as nitrogen, oxygen, or fluorine) and another electronegative atom in a separate molecule or within the same molecule.
The reason why hydrogen bonding is only possible with hydrogen and not with other atoms is because of the unique characteristics of hydrogen. Hydrogen is the smallest and simplest atom, consisting of just one proton and one electron. It also has a low atomic mass.
When hydrogen is bonded to another atom, such as oxygen in a water molecule (H2O), the oxygen atom pulls the shared electrons closer to itself, creating a partial negative charge around the oxygen atom and a partial positive charge around the hydrogen atom. This separation of charge, or polarity, creates an electrostatic attraction between the partially positive hydrogen atom and the partially negative oxygen atom of a neighboring water molecule. This attraction is known as hydrogen bonding.
Other atoms, such as carbon or sulfur, are larger and less electronegative than hydrogen, so the electronegative difference between hydrogen and these atoms is not significant enough to create a strong enough polarity for hydrogen bonding to occur. Thus, hydrogen bonding is unique to hydrogen due to its small size and high electronegativity relative to other elements.