# Why does butanoic acid have a higher boiling point than isobutyric acid?

Why does butanoic acid have a higher boiling point then isobutyric acid, when they have similar molar mass and molecular structure?

Butanoic acid ($$\ce{C4H8O2}$$) has a molar mass of 88.11 g/mol, the boiling point is 163 °C, and intermolecular force of H-bond.

Isobutyric acid ($$\ce{C4H8O2}$$) has a molar mass of 88.11 g/mol, the boiling point is 155 °C, and intermolecular force of H-bond.

• Same reason why n-Butane has a higher boiling point than Isobutane: More intermolecular van der Waals interaction. – Karl Sep 26 '15 at 9:59

• Structuring and packing is usually an argument when talking about the melting point, right? How relevant would it be for liquid $\to$ gas? – Eashaan Godbole Mar 6 at 14:26