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.
In general, linear chains are more easily structured and packed than branched ones.  You need more energy to disturb the more relatively packed structure.This could explain why butanoic acid has a higher boiling point than isobutyric acid, and yet they are isomers.