Question

Identify the correct option regarding enantiomers.
A.Molecules that are mirror images
B.Molecules that have one stereogenic centre
C.Non-superimposable mirror images
D.Non-superimposable constitutional isomers

Answer 1

Molecules having same structural formula but different arrangement of atoms in space is called stereoisomerism and is divided into two: a) Diastereoisomers b) Enantiomers

Complete answer:
First we will discuss some basic terms which we might encounter later. so starting with the term called chiral. A molecule is said to be chiral if it is not superimposable on its mirror image or in other words if all the groups attached to the carbon is different then, it is also termed as chiral. A carbon attached to four different atoms is known as stereogenic centre. The stereoisomers of a compound which are not superimposable on its mirror images, are called enantiomers. From the definition of enantiomer we have understood that these are mirror images but in option (a) it is not mentioned whether these are superimposable or not. So, option a is not correct. A molecule with one stereogenic centre is always chiral and always exists in enantiomeric forms. Option(b) is somewhere a part of it but actually does not give the correct definition of enantiomers.so this option is also incorrect. In constitutional isomers, the isomers have the same molecular formula but differ in constitutional formula and this is not related to mirror images. So we can eliminate option (d).
So, option C is the correct answer here.

Additional information: The stereoisomers of a compound which are not mirror images of each other are called diastereoisomers. A compound having stereogenic centre but optically inactive due to the presence of a plane of symmetry is termed as meso compounds. In meso compounds the plane divides the molecule into two equal halves that are mirror images. This internal compensation makes them optically inactive.

Note: To check whether two images are superimposable or not just the object and place it as it is over its mirror image. Do not rotate the object image while placing it over the mirror image.