Question

Place the following compounds in order of decreasing strength of intermolecular forces: CS₂, NH₃, N₂.

a. CS₂ > NH₃ > N₂
b. NH₃ > CS₂ > N₂
c. CS₂ > N₂ > NH₃
d. NH₃ > N₂ > CS₂

Answer 1

The order of decreasing strength of intermolecular forces is NH₃, CS₂, N₂.

Step-by-step explanation:

The intermolecular forces in a substance determine its strength. In this case, we need to compare the intermolecular forces in CS₂, NH₃, and N₂. CS₂ is a nonpolar molecule and has London dispersion forces, which are relatively weak. NH₃ is a polar molecule with a permanent dipole moment, so it has dipole-dipole forces. N₂ is a nonpolar molecule and also has London dispersion forces. Dipole-dipole forces are stronger than London dispersion forces. Therefore, the compounds can be arranged in order of decreasing strength of intermolecular forces as follows:

1. NH₃
2. CS₂
3. N₂