Answer: Br2 with FeBr3.
- A Br2 only
- B Br2 with FeBr3
- C HBr
- D NaBr
Correct answer: B. Br2 with FeBr3
Explanation: FeBr3 acts as a Lewis acid catalyst in electrophilic substitution of benzene.
Going from a single to a triple bond between carbons increases the s-character of hybridisation (sp³→sp²→sp), shortening the bond and locking the geometry, while increasing π-bond reactivity (alkenes and alkynes readily undergo addition reactions that alkanes don't).
Concept context
The simplest organic compounds made only of carbon and hydrogen. Covers alkanes, alkenes, alkynes, and aromatic compounds like benzene. Learn preparation methods, key reactions, and physical properties.