Chemistry - STEREO ISOMERISM Question with Solution | TestHub

meso-2,3-Butanediol, (2R,3S), has a plane of symmetry (σ) passing through the midpoint of the C₂-C₃ bond, shown by the dashed line in the Fischer projection: the upper half (C₂ with H, OH, CH₃) is the mirror image of the lower half (C₃). In the Newman projection along C₂-C₃ the same plane contains the two CH₃ groups and the C₂-C₃ bond and reflects H into H and OH into OH. The molecule is therefore achiral (optically inactive) even though it has two stereocentres.