Alkenes: geometrical isomerism, electrophilic addition, Markovnikov and peroxide effect
- Which one of the following compounds does not decolourize bromine water? Answer: 1. cyclohexane Key idea: bromine water is decolourised by alkenes (addition) and by activated aromatics (substitution). Styrene: C=C... 1
- The major product formed in dehydrohalogenation reaction of 2-Bromo pentane is Pent-2-ene. This product formation is based on ? Answer: 1. Saytzeff's Rule Key idea: in dehydrohalogenation, the more substituted (more stable) alkene is the major product. This is Saytzef... 1
- The major product of the following chemical reaction is :(CH_3)_2CH-CH=CH_2 + HBr (C_6H_5CO)_2O_2 ? Answer: 1. (CH₃)₂CH-CH₂-CH₂-Br Key idea: with peroxide, HBr adds to alkenes by a free-radical path: anti-Markovnikov (Kharasch peroxide effe... 1
- The compound that will react most readily with gaseous bromine has the formula Answer: 4. C₃H₆ Key idea: gaseous Br₂ adds readily across a C=C bond; a more electron-rich alkene reacts faster. C₃H₆ (propene) beats C₂H₄ b... 1