Identify the relationship between the given pair of molecules:

Which of the following pairs exhibits the phenomenon of $Metamerism$?

Which of the following exhibits chain isomerism?

Compounds with the same molecular formula but differing in their structures are called structural isomers. What type of structural isomerism is shown by $CH_3-S-CH_2-CH_2-CH_3$ and $CH_3-S-CH(CH_3)_2$?

Provide the structures of chain isomers of $C_6H_{14}$ that contain two methyl groups,along with their $IUPAC$ names.

Among the four compounds,$(i)$ acetone,$(ii)$ propanol,$(iii)$ methyl acetate and $(iv)$ propionic acid,the two that are isomeric are