Rank the following compounds in order of decreasing melting point, putting the compound with the highest melting point first.

Question

Quizplus · Accepted Answer

The melting point of a compound is influenced by the strength of the intermolecular forces between its molecules. In general, the stronger the intermolecular forces, the higher the melting point.

Compound III is a polar molecule with hydrogen bonding, which is the strongest intermolecular force. Therefore, it has the highest melting point.

Compound I is a nonpolar molecule with only London dispersion forces, which are weaker than hydrogen bonding. Therefore, it has the lowest melting point.

Compound II is a polar molecule with dipole-dipole forces, which are stronger than London dispersion forces but weaker than hydrogen bonding. Therefore, it has a melting point between Compound I and III.

Thus, the ranking of melting points is III > I > II, and the correct choice is D.

Rank the Following Compounds in Order of Decreasing Melting Point