Question

In which of the following representations given below spatial arrangement of group/atom different from that given in structure $‘a^{\prime }$?

• A.
• B.
• C.
• D.

Answer 1

Answer: (A), (B), (C)

Analysing the stereochemistry of molecules :

Stereochemistry of molecules does not change by even number of exchange of groups attached to chiral carbon or by rotating the molecule by ${180}^{\circ }.$

If we get the same molecule as A by rotating the molecule given in options by ${180}^{\circ }$ or by even number of exchanges between groups around chiral carbon will have the same structure as $A.$

Analysing the options :

By applying one switch to structure $‘a^{\prime },$ we get option $A.$ Thus option $\left(A\right)$ has different structure than $‘a^{\prime }.$



By applying Even number of switches to option $A,$ we get option $C.$ Thus option $\left(A\right)$ has same structure as in option $C.$



By applying Even number of switches to option $A,$ we get option $D.$ Thus option $\left(A\right)$ has same structure as in option $D.$


Thus, structures in Options $\left(A\right),\left(C\right),\left(D\right)$ are the same but different from structure $‘a^{\prime }$

By applying Even number of switches to option $B,$ we get structure $‘a^{\prime }.$ Thus option $\left(B\right)$ has same structure as structure $‘a^{\prime }$

Option $\left(B\right)$ is the same as $‘a^{\prime }.$

Hence, options $\left(A\right),\left(C\right)$ and $\left(D\right)$ are correct.