Question

Among the following compounds, the pair of enantiomers is 

• A. I and IV
• B. I and III
• C. II and III
• D. III and IV

Hint:

Two stereoisomers are enantiomers only when ALL chiral centers have opposite configurations.

Answer 1

The Correct Option is B

Step 1: Identifying chirality.
Each structure contains two stereocenters. Enantiomers are non-superimposable mirror images with opposite configurations at all chiral centers.
Step 2: Compare structures.
Structure I and structure III have identical substituents but opposite configuration at both stereocenters.
This makes them mirror-image forms.
Step 3: Eliminating other choices.
I and IV do not match mirror-image relationship.
II and III differ only at one chiral center (diastereomers).
III and IV are not mirror images.
Step 4: Conclusion.
Thus, I and III form a pair of enantiomers.