Question

How many isomeric vicinal-dihalides are possible for the compound having a molecular formula \[{C_3}{H_6}C{l_2}\]?
A.1
B.2
C.3
D.4

Answer 1

Hint: Vicinal compounds have halogens on adjacent carbons. Elaborate the molecular formula to carefully look at the structure and then decide the correct answer to the problem.

Complete answer:
In the question it is asked to identify how many isomeric vicinal-dihalides are possible for the compound \[{C_3}{H_6}C{l_2}\]. For this you should know what vicinal dihalides are. So vicinal dihalides are those compounds which have halogens present on the adjacent carbons. The vicinal dihalides are obtained as a result of two successive elimination reactions.
Now we will look into the structure from the molecular formula:\[{C_3}{H_6}C{l_2}\] The structure is:

The name of the above compound is 1, 2-dichloropropane. In this structure, we can see that two adjacent carbons are having Cl halogen attach to them so this is a vicinal dihalide. Let us now try to make an isomer of this compound to see whether it is possible or not. So the isomer of this is:

This is the isomer that we get but the name of this compound is also 1,2-dichloropropane, both the compounds drawn above and below are the same. No more isomeric vicinal halides can be drawn for this compound. Hence only 1 isomeric vicinal dihalide is possible for the molecular formula \[{C_3}{H_6}C{l_2}\]
Therefore the correct option \[A.{\text{ }}1\].

Note:
There are also geminal-dihalides. These compounds have halogens present on the same carbon. They also are the result of two successive elimination reactions. Both vicinal-dihalide and geminal-dihalides are important concepts in chemistry.