Tell whether the following pairs of compounds are identical, constitutional isomers, stereoisomers, or unrelated. (a) cis-1,3-Dibromocyclohexane and trans-1,4-dibromocyclohexane (b) 2,3-Dimethylhexane and 2,3,3-trimethylpentane

     (a) Constitutional Isomers

     (b) Constitutional Isomers

Explanation:

Constitutional isomers are also known with the name Structural Isomers. These are the compounds which have same chemical formula but differ in arrangement of atoms i.e. structure.

Both the compounds cis-1,3-dibromocyclohexane and trans-1,4-dibromocyclohexane have the same chemical formula but have different structure as shown in the image below.

In the second case the compounds 2,3-dimethylhexane and 2,3,3-trimethylpentane, both have same chemical formula but have different structures which is shown in the image below.

Thus it is clear that in both the groups (a) and (b) the given compounds are Constitutional Isomers.

it is the most commonly accepted one