Arrange the following compounds in decreasing (highest to lowest) order of boiling point.

Question

Quizplus · Accepted Answer

The boiling point of a compound is directly related to its intermolecular forces, such as hydrogen bonding, dipole-dipole, and London dispersion forces. 
Compound I has the highest boiling point because it has extensive hydrogen bonding between the molecules. Compound III has the next highest boiling point due to strong dipole-dipole interactions. Compound IV has weaker dipole-dipole interactions than III but stronger London dispersion forces, resulting in a lower boiling point than III. Compound II has the lowest boiling point because it only has London dispersion forces. Therefore, the correct order from highest to lowest boiling point is I>III>IV>II.

Arrange the Following Compounds in Decreasing (Highest to Lowest) Order