Answer:
Structural formulas are the graphical representation of chemical compunds and shows the chemical bonds between the atoms of a molecule.
structural formulas of following compunds is attached below:
2,4-dimethylhexane - C8H18, it will have single bonds between carbon atom and will have methyl group at position 2 and 4 carbon.
4-methyl-2-pentene - C6H12, it will have double bond at 2nd carbon and methyl group at 4th carbon.
4-chloro-7-methyl-2-nonyne - C10H17Cl, it will have triple bond at 2nd position, chloride group at 4th carbon and a methyl group at 7th carbon.