Chemistry - STEREO ISOMERISM Question with Solution | TestHub

Compounds (A) and (B) are the two enantiomers of trans-1,2-dimethylcyclopentane: neither has a plane of symmetry, so each pure compound is optically active. Compounds (C) and (D) are the same meso compound, cis-1,2-dimethylcyclopentane (a plane of symmetry bisects the ring through C₃ and the midpoint of the C₁-C₂ bond), so they are optically inactive. An equal mixture of (A) and (B) is racemic and is also optically inactive. Of the choices given, only pure (A) is optically active.