Write the major monohalo product(s) in each of the reactions shown in the figure (three substrate + reagent pairs, labelled i, ii and iv as printed).Reaction (i)Reaction (ii)Reaction (iv) as printed
Solution
Each displayed substrate gives one major monohalide, fixed by its reagent: • addition of HX to the drawn alkene: Markovnikov — the halogen lands on the carbon that forms the more stable (more substituted) carbocation; with HBr + peroxide the orientation reverses (anti-Markovnikov, radical chain); • SOCl2/pyridine on the drawn alcohol: –OH → –Cl at the same carbon (by-products SO2, HCl escape); • NBS (or X2/Δ, light) on the drawn alkene/arene side-chain: substitution at the \textbf{allylic/benzylic} position, the resonance-stabilised radical deciding the site. Write the halogen at the position these rules fix for each figure, leaving the rest of the skeleton unchanged.
CBSE Class 12 Board · 2016 · All India · Subjective
