Question

Which of the following pairs of compounds are enantiomers:

• A.
• B.
• C.
• D.

Answer 1

The Correct Option is A

To identify which of the given pairs of compounds are enantiomers, we need to understand what enantiomers are in the context of organic chemistry. Enantiomers are a type of stereoisomer: molecules that are mirror images of each other but cannot be superimposed onto each other, much like left and right hands. These typically occur when a molecule has a chiral center — a carbon atom bonded to four different groups.

Let's analyze the provided options to determine which pair forms enantiomers:

1. Examine each structure to identify if they possess a chiral center. A chiral center often implies that the molecule might have an enantiomer.
2. The pair of compounds you provided are first visualized:

The above displayed pair of compounds are mirror images of each other. To confirm they are enantiomers, check if they have a chiral center that makes them non-superimposable mirror images. This requires ensuring that the orientation around the chiral center in each compound is different in terms of stereochemistry (R/S configuration).

1. Identify each tetrahedral carbon center, ensuring that all four substituents attached to the carbon atom are different.
2. Check for the mirror image relationship. A simple way is to draw or imagine the mirror line and see if swapping any groups leads to identical structures. If not, they are enantiomers.

Through this analysis, it's been confirmed that the first pair forms enantiomers as they meet the criterion of being non-superimposable mirror images, while the other pairs either do not form mirror images, or are superimposable.

Therefore, the correct answer is:

In conclusion, understanding the concept of chirality and mirror image relationships helps identify enantiomers, which are pivotal in stereochemistry and many biological interactions.