Here are the essential concepts you must grasp in order to answer the question correctly.
Alkene Reactivity
Alkenes are hydrocarbons that contain at least one carbon-carbon double bond. Their reactivity is primarily due to the presence of this double bond, which can undergo electrophilic addition reactions. In the case of HBr addition, the alkene reacts with the hydrogen halide, leading to the formation of a bromoalkane. Understanding the stability of the resulting carbocation is crucial, as it influences whether rearrangements occur during the reaction.
Recommended video:
Alkene Metathesis Concept 1
Carbocation Stability
Carbocations are positively charged carbon species that can form during electrophilic addition reactions. Their stability is determined by the degree of substitution: tertiary carbocations are more stable than secondary, which are more stable than primary. In the context of the question, identifying alkenes that do not lead to carbocation rearrangement means selecting those that form stable carbocations without the possibility of shifting to a more stable form.
Recommended video:
Determining Carbocation Stability
Isotope Effects in Reactions
Isotopes, such as deuterium (D), can influence reaction kinetics and mechanisms. In the context of the question, DBr behaves similarly to HBr in terms of reactivity, but the presence of the heavier isotope can lead to slight differences in reaction rates and product distributions. Understanding how isotopes affect the reaction can help predict whether the same alkyl halide will be formed when using DBr instead of HBr.
Recommended video:
Understanding the hydrogen isotopes.