Question

The number of isomers of dibromobiphenyl (Biphenyl-${{C}_{6}}{{H}_{5}}$) is
A. 8
B. 10
C. 12
D. 4

Answer 1

Hint: The word isomer is derived from two Greek words called iso + mer where iso means equal and mer means parts i.e. equal parts. Isomers are defined as those compounds which have the same chemical formula but different arrangement of molecules and the phenomenon of isomers is known as isomerism.

Complete answer:
Biphenyl is an organic compound which generally forms colorless crystals. It is an aromatic hydrocarbon having the general formula ${{({{C}_{6}}{{H}_{5}})}_{2}}$ it has some distinct pleasant smell like esters.
The structure of biphenyl consists of two phenyl rings connected with each other whereas the given molecule i.e. dibromobiphenyl also contains two connected phenyl rings but with two bromine atoms attached to it and it can be shown as:

There are many type of arrangements can be done which are known as isomer of this compound like in the given figure 1-1’ arrangement is there like this 12 more combinations which can be written as: 2-2’, 2-3, 2-3’, 2-4, 2-4’, 2-5, 2-6, 3-3’, 3-4, 3-4’, 3-5, 4-4’ .
Hence from this we can draw different types of structures of dibromophenyl which are its isomers.

Thus we can say that option C is the correct answer.

Note:
Biphenyl also acts as an intermediate for the production of a number of organic compounds like used as emulsifiers, optical brighteners, crop protection products, and plastics. Biphenyl is generally insoluble in water but can be soluble in some organic solvents.