What is the structural formula of ? trans-oct-4-en-4-ol
trans refers to the configuration of the double bond. The methyl substituents are on opposite sides. Moreover, this alkene holds an alcohol functional group, susceptible to all sorts of reactions!
For instance, it could be brominated, and then deprotonated, followed by an intramolecular reaction to form a cyclic ether. Or, the alcohol group could be oxidized into a ketone via Jones oxidation using chromic acid. The list goes on!