Question

Rank the following molecules from the smallest boiling point to the largest boiling point: CO₂, H₂O, CCl₄, CO.

a) CO, CO₂, CCl₄, H₂O
b) CO₂, CO, CCl₄, H₂O
c) CCl₄, CO₂, CO, H₂O
d) H₂O, CO₂, CO, CCl₄

Answer 1

The correct boiling point order for CO₂, H₂O, CCl₄, and CO, from lowest to highest, is CO₂, CO, CCl₄, H₂O due to an increasing strength of intermolecular forces.

Step-by-step explanation:

To rank the following molecules from the smallest boiling point to the largest boiling point — CO₂, H₂O, CCl₄, CO — we must consider intermolecular forces. Carbon dioxide (CO₂) is a small, linear, nonpolar molecule with only London dispersion forces, thus it usually has a lower boiling point. Carbon monoxide (CO) is a small molecule as well, but it has a triple bond and a small dipole moment, leading to a slightly higher boiling point than CO₂. Carbon tetrachloride (CCl₄) is a larger molecule with stronger London dispersion forces, giving it a higher boiling point than both CO and CO₂. Water (H₂O) has the capability to form strong hydrogen bonds which significantly increases its boiling point compared to the other substances listed. Therefore, the correct order from lowest to highest boiling point is CO₂, CO, CCl₄, H₂O, which makes option b the correct answer.