Stereospecificity in electrophilic addition reactions arises due to the specific orientation or approach of reactants leading to a single stereoisomer as a product. One classic example is the bromination of alkenes, where the intermediate bromonium ion forces the second bromine atom to attack from the opposite side, resulting in anti-addition and a specific stereochemical outcome. The nature of the intermediate and the spatial arrangement of atoms or groups in the reactants dictate the stereochemistry of the products.

Electrophilic and nucleophilic addition reactions involve entities with contrasting electronic characteristics. Electrophilic addition reactions typically involve a substance with electron-rich regions (like alkenes) reacting with electrophiles - electron-poor species. On the contrary, nucleophilic addition reactions involve compounds with electron-poor regions (like carbonyl compounds) reacting with nucleophiles - electron-rich species. Additionally, in electrophilic addition reactions, the reaction starts with the attack on the alkene by the electrophile, whereas in nucleophilic addition, the reaction initiates with the nucleophile attacking the electron-poor centre.

Electrophilic addition reactions play a fundamental role in the synthesis of addition polymers. These polymers are formed from unsaturated monomers, such as alkenes, undergoing an electrophilic addition mechanism which leads to the breaking of the double bond and subsequent chain growth. For instance, poly(ethene), commonly known as polyethylene, is manufactured from ethene monomers that join together through electrophilic addition reactions. The polymerisation process is initiated by a radical, and subsequent monomers add to this radical. The result is a long-chain macromolecule. Such polymers find extensive use in packaging, automotive components, textiles, and countless other applications.

Steric hindrance is a phenomenon where bulky groups around the reactive site can restrict or impede a reaction. In electrophilic addition reactions, if an alkene has large substituents near the double bond, they can physically hinder the approach of the electrophile. As a result, the rate of reaction may decrease. Furthermore, in the case of unsymmetrical alkenes, the steric hindrance can also influence the major product's formation. A bulkier substituent will often direct the electrophile to the less hindered carbon atom, potentially overriding electronic factors such as carbocation stability.

While all alkenes possess a double bond and are generally electron-rich, their reactivity in electrophilic addition reactions can differ based on substituents and their arrangement. Electron-donating groups, such as alkyl groups, increase the electron density of the double bond and make the alkene more reactive towards electrophiles. On the other hand, electron-withdrawing groups can decrease reactivity. Additionally, steric hindrance, as mentioned earlier, can also influence reactivity. However, in general, alkenes are reactive towards electrophilic addition, although the rate and preferred product can vary based on the specific alkene's structure and the electrophile in question.