Question

Why bp of aldehydes and ketones are higher than hydrocarbons?

Answer 1

The boiling and melting point of the compounds depends on the strength of the functional groups, so first we will see at the functional groups to determine the strength of the intermolecular forces. The stronger the forces, the higher the boiling and melting point.

Any alkane has  nonpolar  and  bonds, so it has the weakest intermolecular forces and therefore the lowest boiling point.  While aldehyde or ketone contains >C=O BOND , so it contains a net dipole has higher intermolecular than alkane, and therefore  it has the higher boiling point.