A Level Chemistry OCR Practice Exam

What represents a characteristic of an electrophile in organic chemistry?

1. It donates a pair of electrons during a reaction

2. It accepts a pair of electrons to form a covalent bond

3. It is always a positive ion

4. It does not participate in nucleophilic attacks

The correct answer is: It accepts a pair of electrons to form a covalent bond

In organic chemistry, an electrophile is characterized by its ability to accept a pair of electrons during a chemical reaction to form a covalent bond. This definition stems from the electron-deficient nature of electrophiles, which are generally attracted to regions of high electron density. When an electrophile encounters a nucleophile (an electron-rich species), the nucleophile donates a pair of its electrons to the electrophile, facilitating the formation of new bonds. This interaction is crucial in many reactions, including substitution and addition reactions, where the electrophile's acceptance of electrons is a key step that drives the process forward. While some electrophiles may be positively charged ions, the definition encompasses a broader range of species, including neutral molecules with polar functional groups or electron-deficient atoms. Thus, characterizing the electrophile simply as a positive ion omits the important detail that neutral electrophiles can also engage in these types of reactions.