Final answer:
Hydrocarbons C₂H₆, C₃H₈, and C₄H₁₀ are ranked from lowest to highest boiling point based on the strengths of their London dispersion forces, which increase with molecular size.
Step-by-step explanation:
To rank the compounds from highest to lowest boiling point, we must consider the intermolecular forces acting on them. These compounds are all nonpolar and exhibit London dispersion forces.
The boiling point of a compound is generally higher when the molecule is larger because there are more electrons which can create temporary dipoles leading to stronger dispersion forces. The given hydrocarbons, C₂H₆ (ethane), C₃H₈ (propane), and C₄H₁₀ (butane), should be arranged from lowest to highest boiling point based on their molecular size.
The correct order from lowest to highest boiling point would therefore be C₂H₆ < C₃H₈ < C₄H₁₀ because as the number of carbons increases, so does the molecular size and, consequently, the strength of the London dispersion forces.