Chemistry - STEREO ISOMERISM Question with Solution | TestHub

Ans. (C) 4.

Sol. The molecule, (CH₃CHBr)₂C=C(Cl)CH₃, has two stereocentres. They are constitutionally equivalent, but the (R,S) form is not meso: the plane that would exchange the two halves would also have to swap Cl and CH₃ on the alkene carbon, so no internal compensation exists. Hence all 2² = 4 forms, (R,R), (S,S), (R,S) and (S,R), are distinct.