Answer : A substance that can donate a pair of electrons to form a covalent bond is known as a(n) Lewis-base.
Explanation :
According to the Lewis acid-base theory,
Lewis acid : It is a substance that can accepts pairs of electrons to form a covalent bond.
Lewis-base : It is a substance that can donates pairs of electrons to form a covalent bond.
For example :
[tex]H^++OH^-\rightarrow H_2O[/tex]
In this reaction, [tex]H^+[/tex] ion is Lewis-acid and [tex]OH^-[/tex] ion is a Lewis-base. The [tex]OH^-[/tex] ion donates electrons to [tex]H^+[/tex] ion to form [tex]H_2O[/tex].
Hence, a substance that can donate a pair of electrons to form a covalent bond is known as a(n) Lewis-base.
