Question

Which of the following pairs of compounds is an example of position isomerism?

Options

• but -2-ene and 2-methylprop-1-ene 

• But-2-ene and cis-but-2-ene 

• But-1-ene and but-2-ene

• 2-methylprop-1-ene and but-1-ene

Answer 1

But-1-ene and but-2-ene

Explanation:

But-1-ene and but-2-ene are examples of position isomerism.

\[\ce{CH2 = \underset{But-1-ene}{CH - CH2} - CH3}\]

\[\ce{CH3 = \underset{But-2-ene}{CH = CH} - CH3}\]

They are position isomers because they have a same molecular formula, C₄H₈ but different structural formulas.