Question

What are structural isomers? Draw structural isomers of butane (\( C_4H_{10} \)). Give reason why propane has no structural isomers.

Hint:

Structural isomers differ by the connectivity of atoms in their molecules, while their molecular formula remains the same.

Answer 1

Structural Isomers: Structural isomers are compounds that have the same molecular formula but different structural arrangements of atoms. This means that the connectivity or bonding of atoms is different in each isomer. 
Structural Isomers of Butane: The two structural isomers of butane (\( C_4H_{10} \)) are: n-Butane: A straight chain of 4 carbon atoms. Isobutane (Methylpropane): A branched structure with 3 carbon atoms in a chain and one methyl group (-CH\(_3\)) attached to the second carbon. 
Why Propane Has No Structural Isomers: Propane (\( C_3H_8 \)) has no structural isomers because there is only one way to arrange 3 carbon atoms and 8 hydrogen atoms. Any rearrangement would result in the same compound.