Question

What is the difference between a base and a nucleophile?

Answer 1

A nucleophile is an element or molecule that seeks a positive centre in a chemical reaction, just as the nucleus in an atom since the nucleophile has an electron pair that is accessible for bonding.

A base is a compound that reacts with hydrogen ions to neutralise an acid. The majority of bases are minerals that combine with acids to produce water and salts.

Complete answer:
A nucleophile is an electron-rich species that donates two electrons to carbon and forms a bond with it. A Base is also an electron-rich species, but it gives hydrogen a pair of electrons.
Most nucleophiles are Lewis bases and vice versa, the two are connected. Some strong bases are also good nucleophiles, while some good nucleophiles are weak bases. A species can be both a weak nucleophile and a strong base.
While Nucleophiles and bases are similar and have a similar property, they also have differences.
The differences between a base and nucleophile are:

Base	Nucleophile
They attack acidic protons.	They attack electron-deficient carbons.
They have a lower electronegative charge, are greater in size, and are easier to oxidise.	They have a lower electronegative charge, are greater in size, and are easier to oxidise.
Bases are affected by temperature.	Nucleophiles are affected by speed or electricity.
Bases are involved in the forming of strong bonds.	Nucleophiles are involved in the reaction speed.
Basicity reactions involve bases.	Electrophilicity reactions involve nucleophiles.
Bases are slow chemical mediators that retain an acid-based equilibrium during reversible conditions.	Nucleophiles are quick and immediate chemical mediators required during irreversible conditions.

Note: Nucleophilicity and basicity typically go hand in hand. However, these two words are not interchangeable. There are times where a species is a good nucleophile but a bad base, or vice versa.