Question

Arrange the following in order of increasing boiling point: RbCl, CH3Cl, CH3OH, CH4. A. CH3OH < CH4 < CH3Cl < RbCl B. RbCl < CH3Cl < CH3OH < CH4 C. CH4 < CH3OH < CH3Cl < RbCl D. CH3OH < CH3Cl < RbCl < CH4 E. CH4 < CH3Cl < CH3OH < RbCl

Answer 1

Answer:

E. CH₄ < CH₃Cl < CH₃OH < RbCl

Explanation:

The molecule with the stronger intermolecular forces will have the higher boiling point.

The order of strength of intermolecular forces (strongest first) is

• Ion-Ion
• Hydrogen bonding
• Dipole-dipole
• London dispersion

RbCl is a compound of a metal and a nonmetal. It is an ionic compound, so it has the highest boiling point.

CH₃Cl has a C-Cl polar covalent bond. It has dipole-dipole forces, so it has the second lowest boiling point.

CH₃OH has an O-H bond. It has hydrogen bonding, so it has the second highest boiling point.

CH₄ has nonpolar covalent C-H bonds. It has only nonpolar bonds, so the only attractive forces are London dispersion forces. It has the lowest boiling point.

Thus, the order of increasing boiling points is

CH₄ < CH₃Cl < CH₃OH < RbCl