Question

Which statement best describes the relationship between the molecules shown below? They are not isomers of any kind. They are constitutional isomers. They are the same molecule. They are geometric isomers.

Answer 1

Isomerism means same molecular formula and having different structure. Here the two molecule has same molecular formula, so the first option is not correct. constitutional isomers means chain isomerism,position isomerism or functional group isomerism. chain isomerism is only meant for carbohydrate without any other atoms. here, chlorine is present, hence its not chain isomerism. position isomerism is the change in position of functional group in the molecule. here, we can see that in the molecule left,the chlorine is meta to the alkene whereas in right side molecule, the chlorine is in ortho position. it is position isomerism and hence constitutional isomers.

they are not same because one is 1,3 substituted in benzene and other is 1,2 substituted. so,they are not same.

geometric isomerism is possible for alkene. In the above molecule, alkene part is similar, both are trans to each other.ie; ethyl group is trans to methyl group and benzne ring is trans to other methy group.