How many steroisomers are possible for tetra-sec-buty`1` methane?

Options

A. Five
B. Six
C. Seven
D. Eight

Answer

A

Explanation

Number of chiral carbons `=4` Therefore maximum number of possible stereoisomers `=2^(4) = 16`. There are two sets of enantiomeric pairs :`R R R R` and `SSSS`, and `R R R S` and `SSSR`. The mirror image of `R RSS` in the identical `SSR R`, making this the inactive meso diasteroemer. The latter is a rare example of an achiral compound with on planer or centre of symmetry. It has only an important axis of symmetry. Thus the compound has four optically-active and one optically inactive steroiesomers.