Question

Assertion : trans-Butene on reaction with bromine forms racemic mixture.

Answer 1

With trans-but-2-ene, the product of Br2additionis optically inactive due to the formation of symmetric meso compounds.



In general, for symmetrical alkenes and symmetrical reagents, the addition takes place as :

cis-alkene + syn-addition →  meso

trans-akene + syn-addition →  racemic

cis-alkene + anti-addition  → racemic

trans-alkene + anti-addition → meso