Which of the following is position isomer of CH3−CH2−O||C−CH2−CH3?
Compounds having the same structure of the carbon chain but differing only in the position of the multiple (double or triple) bonds or of the functional group are called positional isomers and the phenomenon is called positional isomerism.
First, check for molecular formula
CH3−CH2−O||C−CH2−CH3⇒C5H10O
CH3CH2CH2CH2CHO⇒C5H10O
CH3−O||C−CH2−CH2−CH3⇒C5H10O
CH3−O−CH2−CH2−CH2−CH3⇒C4H10O
CH3−CH2−O−CH2−CH3⇒C4H100
[Different molecular formula]
Now, for option (a),
Molecular formula is same but the functional group is different, i.e. -CHO.