Question

The total number of configurational isomers of the given compound are:

A. 2

B. 4

C. 6

D. 8

Answer 1

Hint: Configurational isomers are the stereoisomers that cannot be converted into one another by rotation around a single bond in the molecule. There are two types of Configurational isomers. 1) Geometrical isomers and 2) optical isomers.

Complete step by step solution:

Geometrical isomerism is going to show by unsaturated compounds and optical isomerism is going to exhibit by the molecules that are having chiral carbons.

The given molecule contains six carbons, one double bond and two chiral centers.

Now we will talk about geometrical isomerism.

The following are the geometrical isomers of the given compound.

Now there are two forms called Trans and Cis they have mirror images also. So, the geometrical isomers formed are four.

Coming to optical isomers, the given compound has two chiral centers and shown in the below image.

The numbers 1 and 2 represent two chiral centers.

There is a formula to calculate the number of isomers from chiral centers.

Optical isomers = $$2^n$$, here n = number of chiral centers.

We know that in the given compound there are two chiral centers.

Therefore the number of optical isomers = $$2^2=4$$.

Total number of configurational isomers = geometrical isomers + optical isomers.

= 4 +4

= 8.

So, totally 8 configurational isomers are going to form by the given compound.

So, the correct option is D.

Note: Don’t be confused between geometrical isomerism and optical isomerism. The compounds that have double bonds will show geometrical isomerism and the compounds which have chiral centers show the optical isomerism. Both the isomerisms combined are called geometrical isomerism.