Question

Which of the following is an electrophile?
A. ${\text{:CC}}{{\text{l}}_{\text{2}}}$
B. ${\text{C}}{{\text{H}}_{\text{3}}}^{\text{ - }}$
C. ${{\text{H}}_{\text{2}}}{\text{O}}$
D. ${\text{N}}{{\text{H}}_{\text{3}}}$

Answer 1

Electrophile is an electron-deficient species. It tends to accept electrons. Determine the species that has less number of electrons.

Complete answer:
An electrophile is a species having an electron-deficient atom or center. Due to the deficiency of electrons, they tend to gain electrons.

A. The species given in option A is${\text{:CC}}{{\text{l}}_{\text{2}}}$. It is dichlorocarbene. The structure of ${\text{:CC}}{{\text{l}}_{\text{2}}}$ is as follows:

Here, the central carbon atom is surrounded by 6 electrons so we can say that it is an electron-deficient species. So, dichlorocarbene ${\text{:CC}}{{\text{l}}_{\text{2}}}$ is an electrophile.
Thus, option (A) ${\text{:CC}}{{\text{l}}_{\text{2}}}$ is correct.

B. The species given in option B is${\text{C}}{{\text{H}}_{\text{3}}}^{\text{ - }}$. The structure of ${\text{C}}{{\text{H}}_{\text{3}}}^{\text{ - }}$ is as follows:

Here, the central carbon atom is surrounded by 8 electrons so we can say that it is an electron-rich species. So, we cannot consider ${\text{C}}{{\text{H}}_{\text{3}}}^{\text{ - }}$ as an electrophile.
Thus, option (B) ${\text{C}}{{\text{H}}_{\text{3}}}^{\text{ - }}$ is incorrect.

C. The species given in option C is${{\text{H}}_{\text{2}}}{\text{O}}$. The structure of ${{\text{H}}_{\text{2}}}{\text{O}}$ is as follows:

Here, the central oxygen atom is surrounded by 8 electrons so we can say that it is an electron-rich species. So, we cannot consider ${{\text{H}}_{\text{2}}}{\text{O}}$ as an electrophile.
Thus, option (C) ${{\text{H}}_{\text{2}}}{\text{O}}$ is incorrect.

D. The species given in option D is${\text{N}}{{\text{H}}_{\text{3}}}$. The structure of ${\text{N}}{{\text{H}}_{\text{3}}}$ is as follows:

Here, the central nitrogen atom is surrounded by 8 electrons so we can say that it is an electron-rich species. So, we cannot consider ${\text{N}}{{\text{H}}_{\text{3}}}$ as an electrophile.
Thus, option (D) ${\text{N}}{{\text{H}}_{\text{3}}}$is incorrect.

**Hence, the correct option is (A) ${\text{:CC}}{{\text{l}}_{\text{2}}}$.

Note:**
Carbene are neutral species having a carbon atom with two bonds. In carbene central carbon atoms are surrounded by 6 electrons. As the octet of central carbon in carbene is incomplete they are known as electrophile.