Which of the following describes an electrophile?

An electrophile is defined as an electron pair acceptor, which is indicative of its role in chemical reactions. Electrophiles are species that are either positively charged or are neutral but have an incomplete octet, making them eager to accept electrons to achieve stability. This property allows them to react with nucleophiles, which are electron pair donors.

In contrast, a proton donor is typically characterized as an acid, which is not necessarily electrophilic on its own. While nucleophiles are indeed electron pair donors, they do not define the concept of an electrophile. Bases are also related to proton acceptance but are not directly tied to the definition of electrophilicity. Overall, option B accurately captures the essence of an electrophile’s behavior in organic reactions and distinguishes it from other types of chemical species.