Rank the following molecules based on increasing boiling point.

Question

Quizplus · Accepted Answer

Boiling point depends on intermolecular forces, with stronger forces resulting in higher boiling points.

Iodine (I₂) is a nonpolar molecule that experiences only weak London dispersion forces, so it has the lowest boiling point. Thus, I₂ must be the lowest boiling substance and should be ranked last.

Carbon tetrachloride (CCl₄) is a larger and more polar molecule than I₂, so it experiences stronger London dispersion forces. Thus, it should have a higher boiling point than I₂. So, II should be ranked higher than I.

Acetone (CH₃COCH₃) is a polar molecule that can form dipole-dipole interactions in addition to London dispersion forces, making its intermolecular forces stronger than CCl₄. Thus, it should have a higher boiling point than CCl₄. So, III should be ranked higher than II.

Butanal (CH₃CH₂CH₂CHO) is also a polar molecule but contains an additional -CHO group, enabling it to participate in hydrogen bonding. So, IV should have the highest boiling point, and it should be ranked higher than III.

Rank the Following Molecules Based on Increasing Boiling Point