Question

Draw all the structural and geometric (cis-trans) isomers of bromochloropropene.

Short answer

There are thirteen possible structural and geometric isomers of bromochloropropane as shown below:

Step-by-step solution

Definition of isomerism.

Isomerism refers to the presence of molecules with the same number of atoms of the same type (and hence the same formula) but different chemical and physical characteristics.

The structural and geometric (cis-trans) isomers of bromochloropropene.

The structural isomersare the ones that have a similar number of atomsbut are completely different compounds.

Here, the compounds have atoms arranged differently and therefore they have all the physical and chemical properties different.

There are 8 structural isomers and from them, 5 can form geometrical isomers.

In geometric isomerism, the compounds have atoms bonded similarly. Here, the two bulky groups on the doubly-bonded carbon atoms are one time on the opposite side (TRANS) and one time on the similar side (CIS).

The terminal alkene with 2-H atoms cannot form cis-trans isomers as the condition for CIS-TANS isomerism is that both the doubly-bonded carbon atoms should be attacked to two different substituents. The example of the compounds that cannot show cis-trans isomerism is shown below.

These are structural isomersbut cannot show geometrical isomerism.

The structures that can give structural as well asgeometric (CIS-TRANS) isomerism are shown below.

Therefore, in total there are thirteen possible isomers of bromochloropropane.