Consider the isomers of pentane (). Which isomer exhibits the highest melting point and which exhibi — Hydrocarbons Chemistry Question
Question
Consider the isomers of pentane ($C_5H_{12}$). Which isomer exhibits the highest melting point and which exhibits the highest boiling point, respectively?
💡 Solution & Explanation
The boiling point of alkanes decreases with increased branching because branching reduces the molecule's surface area and van der Waals dispersion forces; thus, n-pentane has the highest boiling point. Conversely, the melting point is heavily dependent on crystal lattice packing. Neopentane is highly branched and nearly spherical, allowing it to pack very closely in the solid state, giving it the highest melting point among the isomers.