Question

What kind of a reaction occurs between a nucleophile and an electrophile?
A. Ionic
B. Covalent
C. Coordinate covalent
D. Metallic

Answer 1

Hint: The nucleophile is an electron donating species that is attracted towards an electron deficient center so as to reduce its own electron density. Electrophiles are electron deficient species that have a tendency to accept electrons from an electron rich source.

Complete answer:
The reactions between nucleophiles that are electron rich in nature and electrophiles that are electron deficient in nature are mainly studied under organic chemistry which mainly involves the formation of covalent bonds between atoms.
A simple donation and acceptance of electrons takes place between a nucleophile and an electrophile. A nucleophile may contain an excess of electrons in the form of negative charge (an ionic species) or in the form or a lone pair of electrons (neutral species). Similarly, an electrophile may be inherently electron deficient like Lewis acid centers (with incomplete octets) or may contain a positive charge (a cationic species).
Therefore, the interaction between a nucleophile and an electrophile may or may not be purely electrostatic in nature and an ionic reaction does not seem to occur.
Covalent interactions require an equal sharing of electrons between two centers which is not possible in the case of nucleophiles and electrophiles, therefore the interaction cannot be purely covalent in nature.
The reaction mainly involves transfer or donation of a pair of electrons from the nucleophile to an electrophile which is partially covalent and partially ionic and is known as a coordinate covalent bond.
So, the correct answer is “Option C”.

Note:
Metallic bonding is only restricted to metallic species that are highly electropositive in nature. This type of bonding is responsible for the compact structure and hardness associated with metallic lattices. The nucleophiles and electrophiles studied under organic chemistry do not contain any pure metallic species.