CN- (cyanide ion) is classified as a Lewis base. A Lewis base is a substance that can donate a pair of electrons to form a covalent bond. In the case of CN-, the carbon atom has a lone pair of electrons that it can donate to a Lewis acid, which is a substance that can accept a pair of electrons.
Here’s a simple explanation:
- Lewis Base: CN- has a lone pair of electrons on the carbon atom. This lone pair can be donated to a Lewis acid, making CN- a Lewis base.
- Lewis Acid: CN- does not have the ability to accept electrons, so it cannot act as a Lewis acid.
In summary, CN- is a Lewis base because it can donate a pair of electrons to form a covalent bond with a Lewis acid.