Answer: A molecular compound.
Acetaminophen is an interesting compound in that has at least 3 specific types of functional groups.
LOOK UP THE STRUCTURE FOR Acetaminophen. It will make it clearer.
Or,
Draw a Benzene ring. This is the archetypal “aromatic ring”. 6 carbons in a ring with 3 alternating unsaturations or “double bonds”. It is planar, and follows the 2n + 2 rule for aromaticity. (Where n = 2, so (2 x 2) + 2 = 6. (The three unsaturations; you may not have seen all this yet, but you will, so bear with me).
The 2nd functional group, a -OH or a Hydroxyl group, behaves VERY differently on an aromatic ring than on an alkane. The resonance stabilization (of the aromatic ring), allows the Hydrogen to disassociate from the -OH to yield Aromatic ring—O - + H+ when it is in a polar solution, like water. Phenol is the simplest example.
3rd functional group is a methyl Amide. This amide is —NH—COCH3 (trans). Amides are a N bonded to a H and a carbon bearing a double bonded Oxygen, and the same carbon, in this example, a methyl group. There is a resonance between the N and O, but the structure you see is the lowest energy and most stable. Place the —OH Exactly opposite on the ring to the methyl amide, in the 1,4, or para position.
This may be overdoing it, but it never hurts to learn functional groups as soon as possible.
