And if they are nucleophilic substitution reactions as well, then why do we not call them "electrophilic and nucleophilic addition reactions of alkenes"?

Consider the reaction between ethene and HBr. The HBr bond undergoes heterolytic fission resulting in a bromide anion and hydrogen cation. The hydrogen cation quickly forms a dative bond with one of the carbon atoms (the hydrogen atom is the electrophile and it got added to ethene). After that, the bromide anion (which is a nucleophile) forms a dative bond with the other carbon atom (acting like a nucleophile) and is "added" to the structure.

So why is such a reaction called "electrophilic addition" even though nucleophilic addition is also taking place? Why isn't it called "electrophilic & nucleophilic addition"?

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    $\begingroup$ Substrate is alkene. Alkene get saturated so it is an addition reaction. first group to add is proton (in your example) which is a electrophile. Therefore, it is an electriphilic addition. The rest is to complete reaction. Think about redox reaction. There can't be a reduction without oxidation. Calling the reaction is with respect to one molecule. Here it is alkene. $\endgroup$ Commented Jan 29, 2022 at 21:16


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