No, a hydrogen bond can be formed between a hydrogen atom in one molecule and a highly electronegative atom (usually oxygen, nitrogen, or fluorine) in another molecule. While hydrogen bonds are commonly observed between water molecules, they can also form between other molecules such as DNA bases, proteins, and organic compounds.
Yes, hydrogen bonds can only be formed between one water molecule and another molecule or atom that is either oxygen or nitrogen. Hydrogen bonds are a type of intermolecular force that occurs when a hydrogen atom, which is already bonded to an electronegative atom (such as oxygen or nitrogen), is attracted to a neighboring electronegative atom. In the case of water, the oxygen atom in one water molecule can form a hydrogen bond with a hydrogen atom in another water molecule. These hydrogen bonds contribute to the unique properties of water, such as its high boiling point and surface tension.
