Decide which of the substances listed can form hydrogen bonds?
H20 H2O2
HF NH3
NaF H2
NO CH4
H2O , HF , NH3 , will.
H2 & CH4 will not.
NO will also form a hydrogen bond.
What about H2O2?
To determine which substances can form hydrogen bonds, we need to understand the conditions necessary for hydrogen bonding. Hydrogen bonding occurs when a hydrogen atom is bonded to an electronegative atom (such as nitrogen, oxygen, or fluorine) and is attracted to another electronegative atom in a different molecule.
Let's analyze each substance:
1. H2O (water): Water can form hydrogen bonds because it has two hydrogen atoms bonded to an oxygen atom. Oxygen is highly electronegative, creating a significant difference in electronegativity between hydrogen and oxygen, allowing for hydrogen bonding.
2. H2O2 (hydrogen peroxide): Hydrogen peroxide can also form hydrogen bonds because it has two hydrogen atoms bonded to an oxygen atom. Similar to water, the presence of electronegative oxygen allows for hydrogen bonding.
3. HF (hydrofluoric acid): HF can form hydrogen bonds due to the presence of a highly electronegative fluorine atom bonded to a hydrogen atom.
4. NH3 (ammonia): Ammonia can form hydrogen bonds because it has a nitrogen atom with lone pairs of electrons and three hydrogen atoms attached to it. Nitrogen is electronegative, and the lone pairs on the nitrogen atom can attract hydrogen atoms from other ammonia molecules, resulting in hydrogen bonding.
5. NaF (sodium fluoride): Sodium fluoride cannot form hydrogen bonds because the fluorine atom, although electronegative, is not directly bonded to hydrogen. Hydrogen bonding requires the presence of a hydrogen atom bonded to an electronegative atom.
6. H2 (hydrogen gas): Hydrogen gas cannot form hydrogen bonds because it consists of diatomic hydrogen molecules, which do not contain an electronegative atom bonded to hydrogen.
7. NO (nitric oxide): Nitric oxide cannot form hydrogen bonds because it lacks a hydrogen atom bonded to an electronegative atom.
8. CH4 (methane): Methane cannot form hydrogen bonds because all the hydrogen atoms are bonded to carbon, which is not electronegative enough to enable hydrogen bonding.
Therefore, based on the analysis above, the substances that can form hydrogen bonds are:
- H2O (water)
- H2O2 (hydrogen peroxide)
- HF (hydrofluoric acid)
- NH3 (ammonia)