Which of the following reagents undergo addition across a carbon-carbon double bond strictly via an — Reaction Mechanism Chemistry Question

💡 Solution & Explanation

$Br_2/CCl_4$ and dilute $H_2SO_4$ proceed via classical electrophilic addition, forming halonium or carbocation intermediates respectively. $HBr$ with peroxides proceeds via a free radical addition mechanism. Hydroboration ($BH_3$) proceeds via a concerted, four-center molecular addition pathway, not a stepwise electrophilic addition.