Final answer:
Hydrogen bonds can form in substances where hydrogen is covalently bonded to highly electronegative atoms such as N, O, or F. Ammonia (NH3) can form hydrogen bonds due to the presence of nitrogen, while substances like methane (CH4), diatomic hydrogen (H2), and hydrogen iodide (HI) cannot.
Step-by-step explanation:
Hydrogen bonds can be found between molecules of various substances that contain highly electronegative atoms such as nitrogen (N), oxygen (O), and fluorine (F) bonded to hydrogen (H). Among the substances given (NH3, H2, HI, CH4), ammonia (NH3) is capable of forming hydrogen bonds because it has a nitrogen atom bonded to hydrogen atoms. This allows for the formation of hydrogen bonds between the hydrogen of one molecule and the nitrogen of another. Methane (CH4) and diatomic hydrogen (H2) cannot form hydrogen bonds because carbon and hydrogen are not sufficiently electronegative, and HI involves iodine which is less electronegative compared to N, O, or F. The hydrogen bonding in ammonia occurs between the nitrogen atom and hydrogen atom of another NH3 molecule, similar to how hydrogen bonds form in other compounds with N-H bonds.