Question

is the smallest alkane that can show structural isomerism.

• A. Butane
• B. Propane
• C. Pentane

Answer 1

The correct option is A Butane

Structural isomers are compounds with the same molecular formula but different structures. Butane is the smallest alkane that can show isomerism and has a total of two isomers : n-butane and 2-methyl propane (also called isobutane), as shown below.

Although propane is the smallest alkane out of the given options, it does not show structural isomerism. This is because it cannot be arranged in any other way to form a new straight chain or branched compound.