Answer:
Reaction mechanisms are shown below.
Explanation:
Alkene gives nucleophilic addition reaction with strong protic acid.
Proton from a strong protic acid ruptures pi-bond in alkene and makes a new C-H sigma bond and thereby produces a carbocation.
Lone pair on halogen atom first adds onto double bond by rupturing the pi-bond and this pi-bond electrons then simultaneously substitutes a halogen atom from diatomic molecule of halogen to produce a cyclic halogenium cation by forming two new C-X sigma bonds. (X=halogen atom)
Reaction mechanism has been shown below.
