73. Which one of the following molecules has the strongest intermolecular force of attraction?

A. [tex]O_2[/tex]
B. [tex]NH_3[/tex]
C. [tex]SO_2[/tex]
D. [tex]CH_4[/tex]



Answer :

To determine which of the given molecules has the strongest intermolecular force of attraction, we need to analyze the types of intermolecular forces present in each molecule. There are different types of intermolecular forces including London dispersion forces, dipole-dipole interactions, and hydrogen bonding. The strength of these forces varies, with hydrogen bonding being the strongest among them.

Let's look at each molecule:

A. [tex]\( O_2 \)[/tex] (Oxygen gas)
- [tex]\( O_2 \)[/tex] is a non-polar molecule.
- The only type of intermolecular force present in non-polar molecules is London dispersion forces, which are relatively weak.

B. [tex]\( SO_2 \)[/tex] (Sulfur dioxide)
- [tex]\( SO_2 \)[/tex] is a polar molecule because of its bent shape and the difference in electronegativity between sulfur and oxygen.
- It has dipole-dipole interactions which are stronger than London dispersion forces but weaker than hydrogen bonds.

C. [tex]\( NH_3 \)[/tex] (Ammonia)
- [tex]\( NH_3 \)[/tex] is a polar molecule and contains nitrogen-hydrogen bonds.
- The [tex]\( N-H \)[/tex] bond allows for hydrogen bonding, which is the strongest type of intermolecular force.

D. [tex]\( CH_4 \)[/tex] (Methane)
- [tex]\( CH_4 \)[/tex] is a non-polar molecule since it has symmetrical tetrahedral geometry with equal distribution of charge.
- It only exhibits London dispersion forces.

Among the options, [tex]\( NH_3 \)[/tex] (Ammonia) exhibits hydrogen bonding, which is the strongest type of intermolecular force present in the given molecules. Therefore, [tex]\( NH_3 \)[/tex] has the strongest intermolecular force of attraction.

Thus, the answer is:

B. [tex]\( NH_3 \)[/tex]