* Structure: Ammonia has a central nitrogen atom bonded to three hydrogen atoms. The nitrogen atom has a lone pair of electrons.

* Hydrogen Bonding: Hydrogen bonding occurs when a hydrogen atom is covalently bonded to a highly electronegative atom (like nitrogen, oxygen, or fluorine) and is attracted to a lone pair of electrons on another electronegative atom in a nearby molecule.

* Ammonia's Capabilities:

* Donor: The hydrogen atoms in ammonia can act as hydrogen bond donors because they are covalently bonded to the electronegative nitrogen atom.

* Acceptor: The lone pair of electrons on the nitrogen atom can act as a hydrogen bond acceptor.

* Overall: Therefore, each ammonia molecule can potentially form one hydrogen bond with each of its three hydrogen atoms and one hydrogen bond with its lone pair of electrons, resulting in a total of four hydrogen bonds.

It's important to note that the number of hydrogen bonds an ammonia molecule can form in practice might be less than four due to steric hindrance and the arrangement of surrounding molecules.