Enantiomers

Enantiomers are a type of stereoisomers, which are molecules that have the same molecular formula and connectivity but differ in the arrangement of atoms in space. Enantiomers specifically refer to non-superimposable molecules that are mirror images of each other.

Chiral Carbon

A chiral carbon is a carbon atom that is bonded to four different substituents. This means that the carbon atom is asymmetric, and its mirror image cannot be superimposed onto the original molecule. Chiral carbons are an important concept in understanding enantiomers.

Non-superimposable Molecules

Non-superimposable molecules are those that cannot be placed on top of each other in a way that all atoms align perfectly. In other words, the molecules cannot be superimposed onto one another. This property arises due to differences in the arrangement of atoms in three-dimensional space.

Non-superimposable Constitutional Isomers

Constitutional isomers are molecules with the same molecular formula but different connectivity. Non-superimposable constitutional isomers refer to molecules that have different connectivity and cannot be superimposed onto each other. However, they may or may not be mirror images of each other.

Explanation of Correct Answer

The correct answer is option 'D' - non-superimposable molecules that are mirror images of one another. This is because enantiomers are specifically defined as molecules that are non-superimposable mirror images. They have the same connectivity and molecular formula, but differ in their spatial arrangement due to the presence of a chiral carbon.

Enantiomers possess identical physical and chemical properties, except for their interaction with other chiral molecules such as chiral catalysts or chiral receptors. This property is due to their mirror image relationship, where one enantiomer rotates plane-polarized light clockwise (dextrorotatory) and the other rotates it counterclockwise (levorotatory).

Enantiomers are often denoted using the prefixes (R)- and (S)- based on the Cahn-Ingold-Prelog (CIP) priority rules. These rules assign priorities to substituents on a chiral carbon based on atomic number, and the molecule is then oriented so that the lowest priority substituent is pointing away. If the remaining substituents are arranged in a clockwise direction, it is assigned (R)-configuration, and if they are arranged counterclockwise, it is assigned (S)-configuration.

In conclusion, enantiomers are non-superimposable molecules that are mirror images of each other. They possess the same molecular formula and connectivity, but differ in their spatial arrangement due to the presence of a chiral carbon.