(i) Reaction of HBr with propene in the presence of peroxide gives n -propyl bromide. This addition reaction is an example of an anti-Markownikoff's addition reaction. ‌R−O−O−R‌
∆
⟶
2R−O∘ ‌2R−O∘+H−Br⟶R−OH+Br∘
(ii) Reaction of n-propyl bromide with Mg gives propyl magnesium bromide (Grignard reagent).
CH3CH2CH2‌Br
Propyl bromide
+Mg⟶CH3CH2CH2‌MgBr (iii) Reaction of propyl magnesium bromide with propanal gives nucleophilic additon reaction.
(iv) Reaction of hexan-3-ol with oxidising agent CrO3 .