Final answer:
The reaction in question is hydration of alkenes where water adds to an alkene in the presence of an acid catalyst to form an alcohol. The electrophilic addition mechanism involves the formation of a carbocation intermediate, nucleophilic attack by water, and deprotonation to form the alcohol product. The carbocation's stability affects regioselectivity in the reaction.
Step-by-step explanation:
Electrophilic Addition Mechanism and Hydration of Alkenes
Electrophilic addition reactions are a type of reaction where an electron-rich species, such as an alkene or alkyne, reacts with an electrophile to form a new compound. In the specific case of hydration of alkenes, the reaction involves the addition of water (H2O) to the double bond (C=C) of an alkene. The reaction requires an acid catalyst; sulfuric acid (H2SO4) is commonly used because its conjugate base HSO4- is a poor nucleophile. This means that water, which is also a relatively poor nucleophile but present in greater concentration, will preferentially attack the carbocation intermediate formed during the mechanism.
The mechanism for the hydration reaction involves three key steps:
- Protonation of the alkene to generate a carbocation intermediate.
- Water acts as a nucleophile and attacks the carbocation, forming an oxonium ion.
- Deprotonation of the oxonium ion by another water molecule to give the final alcohol product.
The nature of the carbocation intermediate is important for understanding regioselectivity and for predicting which alcohol will form. Greater substitution on the carbocation leads to a more stable intermediate and this influences the outcome of the reaction.