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Two acyclic molecules with molecular formula C8H8 are such that one shows enantiomerism and the other shows diastereoisomerism. The structural relationship between these two molecules is:

1. Chain Isomers
2. Positional Isomers
3. Geometrical Isomers
4. Conformation isomers

Correct answer: Positional Isomers

Solution

Both molecules are acyclic constitutional isomers of C8H8. They have the same type of functional groups but differ in the position of double bonds or substituents — making them positional isomers. This arrangement allows one to possess a chiral centre (enantiomerism) while the other has restricted rotation about a double bond (geometric/diastereoisomerism).

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