Which of the following is position isomer of
CH3−CH2−CH=CH2:
Compounds having the same structure of the carbon chain but differ only in the position of the multiple (double or triple) bonds or the functional group is called positional isomers and the phenomenon is called positional isomerism.
CH3−CH2−CH=CH2⇒C4H8
Checking for all the options.
CH3−CH2−CH2−CH2−CH3 ⇒C5H12
CH3−CH2−CH2−CH3⇒C4H10
CH3−CH=CH−CH3⇒C4H8
CH3−CH|CH3−CH2−CH3⇒C5H12
There is a difference in the position of the double bond.
Hence, CH3−CH=CH−CH3⇒C4H8 is the correct answer.