Reaction of an alkene with HX yields which product?

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Multiple Choice

Reaction of an alkene with HX yields which product?

When an alkene reacts with HX, the reaction is an electrophilic addition across the carbon–carbon double bond. The proton (H+) from HX adds first to one carbon of the double bond to form the most stable carbocation, and then the halide (X−) attacks that carbocation. This process converts the C=C into a single C–C bond and introduces one hydrogen and one halogen, giving a haloalkane. The halogen ends up on the more substituted carbon (Markovnikov rule), so the product is a haloalkane (for example, propene plus HBr gives 2-bromopropane as the major product). This isn’t an alkane or an alcohol, and the double bond is not retained, so the haloalkane is the correct outcome.

When an alkene reacts with HX, the reaction is an electrophilic addition across the carbon–carbon double bond. The proton (H+) from HX adds first to one carbon of the double bond to form the most stable carbocation, and then the halide (X−) attacks that carbocation. This process converts the C=C into a single C–C bond and introduces one hydrogen and one halogen, giving a haloalkane. The halogen ends up on the more substituted carbon (Markovnikov rule), so the product is a haloalkane (for example, propene plus HBr gives 2-bromopropane as the major product). This isn’t an alkane or an alcohol, and the double bond is not retained, so the haloalkane is the correct outcome.

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