Question

Choose the correct statement among the following for the product formed, when cis-2-butene is reacted with bromine in $CC{l}_4$.

• A. Number of the stereoisomers of the product formed are 2, namely $d$-2,3-dibromobutane and $l$-2,3-dibromobutane
• B. Number of the stereoisomers of the product formed are 2,namely D-2,3-dibromobutane and L-2,3-dibromobutane
• C. Three stereoisomers of the product are possible, $d,l$ and meso
• D. Number of the stereoisomers of the product formed are4, namely
  $d$-2,3-dibromobutane,
  $l$-2,3-dibromobutane,
  $d$-2,2-dibromobutane,
  $l$-2,2-dibromobutane.

Answer 1

The correct option is A Number of the stereoisomers of the product formed are 2, namely $d$-2,3-dibromobutane and $l$-2,3-dibromobutane

Halogens like Br, Cl and I add up to alkenes to form vicinal dihalides. Addition of halogens to alkenes​ is an example of electrophilic​ addition reaction. Addition of two substituents to​ multiple bonded C atoms from the ​opposite sides of the multiple bond is known as anti-addition.
When anti addition takes place to a symmetrical cis alkene or unsymmetrical alkene (both cis and trans), then racemic mixture is formed.