Which of the following molecules can form hydrogen bonds?
• HI
• СН4
• ВНз
O NaH
• NH3
The molecules that can form hydrogen bonds are NH3 (ammonia) and HI (hydrogen iodide).
Hydrogen bonds can form between a hydrogen atom bonded to an electronegative atom (usually nitrogen, oxygen, or fluorine) and another electronegative atom. Let's go through each molecule one by one to determine if it can form hydrogen bonds.
- HI: This molecule consists of hydrogen (H) bonded to iodine (I). Since iodine is less electronegative than nitrogen, oxygen, or fluorine, it cannot form hydrogen bonds.
- CH4: This molecule consists of carbon (C) bonded to four hydrogen atoms (H). Since carbon is not electronegative, CH4 cannot form hydrogen bonds.
- BN3: This molecule consists of boron (B) bonded to three nitrogen atoms (N). Although nitrogen is electronegative, boron cannot form hydrogen bonds because it lacks a hydrogen atom that can participate in hydrogen bonding.
- NaH: This molecule consists of sodium (Na) bonded to hydrogen (H). Since sodium is a metal and not electronegative, NaH cannot form hydrogen bonds.
- NH3: This molecule consists of nitrogen (N) bonded to three hydrogen atoms (H). Nitrogen is electronegative, and since NH3 has a hydrogen atom bonded to nitrogen, it can form hydrogen bonds.
Therefore, the only molecule from the given options that can form hydrogen bonds is NH3.
To determine which of the molecules can form hydrogen bonds, we need to understand the requirements for hydrogen bonding. Hydrogen bonding occurs when hydrogen is bonded to a highly electronegative atom (such as nitrogen, oxygen, or fluorine) and there is a lone pair of electrons on an adjacent electronegative atom.
Now, let's analyze each of the molecules you provided:
• HI: Hydrogen is bonded to iodine (I), which is highly electronegative. Therefore, HI can form hydrogen bonds.
• CH4: Hydrogen is bonded to carbon (C), which is not highly electronegative and does not have a lone pair of electrons. Hence, CH4 cannot form hydrogen bonds.
• BH3: Hydrogen is bonded to boron (B), which is not highly electronegative, and boron does not have a lone pair of electrons. Therefore, BH3 cannot form hydrogen bonds.
• NaH: Hydrogen is bonded to sodium (Na), which is not highly electronegative and does not have a lone pair of electrons. Hence, NaH cannot form hydrogen bonds.
• NH3: Here, hydrogen is bonded to nitrogen, which is highly electronegative. Additionally, nitrogen has a lone pair of electrons. Thus, NH3 can form hydrogen bonds.
So, the molecules that can form hydrogen bonds are HI and NH3.