Question

Ignoring ring compounds, which isomer of C₂H₄O₂ should boil at the lowest temperature?

Short answer

The isomer methyl formate boil at the lowest temperature.

Step-by-step solution

Structure of the isomers

We can draw five isomers with molecular formula C₂H₄O₂, excluding ring compounds.

Determine the isomer with lowest boiling point

We can see that all isomers except methyl formate can form hydrogen bonds.

If we consider that the strength of the intermolecular bonds affects the boiling point, it can be assumed that the methyl formate has the lowest boiling point because it cannot participate in hydrogen bonds.

(The stronger the intermolecular bonds between the molecules, the higher the boiling point.). Hence, methyl formate boil at the lowest temperature.