12. Fats and oils consist of long hydrocarbon chains attached to ester functional groups. (a) What do the terms saturated, unsaturated, and polyunsaturated imply about the structures of the hydrocarbon tails in fats and oils? (b) Predict the chemical reaction used to prepare partially hydrogenated vegetable oils.

13. Explain the observed trend in the boiling points of straight-chain alkanes based on the strength of their intermolecular forces.