Question

Number of molecules from the following which can exhibit hydrogen bonding is ______. (nearest integer)

Answer 1

Correct Answer: 5

The question asks for the number of molecules that can exhibit hydrogen bonding. Hydrogen bonding occurs in molecules where hydrogen is directly bonded to a highly electronegative atom like nitrogen (N), oxygen (O), or fluorine (F). Let's examine each molecule:

• CH₃OH (Methanol): Contains an OH group. Hydrogen is bonded to oxygen, so it can form hydrogen bonds.
• H₂O (Water): Contains two OH bonds, allowing it to form hydrogen bonds.
• C₂H₆ (Ethane): Lacks N, O, or F bonded to hydrogen, so no hydrogen bonding is present.
• C₆H₅NO₂ (Nitrophenol): Contains an OH group. Hydrogen is bonded to oxygen, allowing hydrogen bonding.
• HF (Hydrogen Fluoride): Contains hydrogen bonded to fluorine, capable of forming hydrogen bonds.
• NH₃ (Ammonia): Contains N bonded to hydrogen, which enables hydrogen bonding.

Counting the molecules that can exhibit hydrogen bonding, we have: CH₃OH, H₂O, C₆H₅NO₂, HF, and NH₃.

Thus, the total number of molecules capable of hydrogen bonding is 5, which falls within the given range [5,5].

Answer 2

Molecules that exhibit hydrogen bonding:
\[\text{CH}_3\text{OH}, \, \text{H}_2\text{O}, \, \text{HF}, \, \text{NH}_3, \, \text{C}_6\text{H}_5\text{NO}_2\]
Benzene (C$_6$H$_6$) does not form hydrogen bonds. Total number of molecules exhibiting hydrogen bonding:
\[5\]