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 molecules sharing the same molecular formula but differing in how their atoms are connected. The atom-to-atom bonding patterns distinguish them.
Structural Isomers of Butane: Butane (\( C_4H_{10} \)) has two structural isomers: n-Butane, featuring a straight chain of 4 carbons, and Isobutane (Methylpropane), a branched structure with a 3-carbon chain and a methyl group (-CH\(_3\)) linked to the second carbon. 
Why Propane Has No Structural Isomers: Propane (\( C_3H_8 \)) lacks structural isomers because its 3 carbon atoms and 8 hydrogen atoms can only be arranged in a single way; any other arrangement yields the same compound.