Answer:
1,1-, (Z)-1,2-, and (E)-1,2-dibromoethene
Explanation:
Their structures are shown below.
The 1,2-dibromoethenes (2 and 3) are positional isomers
of 1,1-dibromoethene (1).
(Z)-1,2-dibromoethene (2) and (E)-1,2-dibromoethene (3) are stereoisomers (geometric isomers) of each other.
