The reaction of an alkene with bromine water is a characteristic electrophilic addition. The process unfolds as follows:
1. Alkene Structure: - Alkenes possess a carbon-carbon double bond, characterized by electron richness and nucleophilic behavior. The pi-electrons of this double bond exhibit high reactivity towards electrophiles.2. Reaction with Bromine: - Bromine (\( \text{Br}_2 \)) functions as an electrophile. Upon reaction with an alkene, the double bond cleaves, forming a transient three-membered bromonium ion intermediate. This unstable intermediate rapidly reacts with a bromide ion (\( \text{Br}^- \)) present in the bromine water. - The bromide ion nucleophilically attacks the more stable carbon of the bromonium ion, resulting in the formation of a dibromoalkane. Both carbon atoms originally part of the double bond are now bonded to bromine atoms.
3. Primary Product: - The predominant product of this reaction is a dibromoalkane, achieved through the addition of two bromine atoms across the double bond.4. Inaccurate Options: - Option (1) "Alkane" is erroneous; this reaction does not involve hydrogenation, which is the process converting alkenes to alkanes. - Option (3) "Alcohol" is incorrect; alcohol synthesis necessitates a distinct reaction pathway, such as hydration. - Option (4) "Bromoalkene" is invalid; the reaction culminates in the addition of two bromine atoms, not a single one.