To determine which molecule can form hydrogen bonds with others like it, we need to understand the conditions necessary for hydrogen bonding. Hydrogen bonding occurs under specific circumstances:
1. There must be a hydrogen atom covalently bonded to a highly electronegative atom such as nitrogen (N), oxygen (O), or fluorine (F). This creates a partial positive charge on the hydrogen.
2. This hydrogen atom can then interact with a lone pair of electrons on a nearby electronegative atom (N, O, or F) in another molecule.
Let’s analyze each molecule:
A. HCl (Hydrochloric acid):
Hydrochloric acid can form hydrogen bonds where hydrogen is bonded to chlorine. However, chlorine is less electronegative compared to nitrogen, oxygen, and fluorine. Additionally, HCl typically forms ionic bonds in aqueous solutions and doesn't form hydrogen bonds with other HCl molecules effectively.
B. CO₂ (Carbon dioxide):
Carbon dioxide does not have hydrogen atoms. It consists of one carbon atom double-bonded to two oxygen atoms. Since hydrogen is absent, there is no possibility of hydrogen bonding.
C. CF₄ (Carbon tetrafluoride):
Carbon tetrafluoride consists of a single carbon atom bonded to four fluorine atoms. Like CO₂, CF₄ also lacks hydrogen atoms, making hydrogen bonding impossible.
D. NH₃ (Ammonia):
Ammonia consists of one nitrogen atom bonded to three hydrogen atoms. Nitrogen is highly electronegative, leading to a significant partial positive charge on the hydrogen atoms. This allows hydrogen atoms in one NH₃ molecule to form hydrogen bonds with the lone pair of electrons on the nitrogen atom in another NH₃ molecule. This fits the criteria for hydrogen bonding perfectly.
Given the above analysis, the molecule that can form hydrogen bonds with others like it is:
D. NH₃ (Ammonia)
