Question

Substance that donates a pair of electrons to form coordinate covalent bond is called

Answer 1

two atoms donates electrons to form dative bond.not substance

Answer 2

Answer: The substance is termed as ligand.

Explanation:

A bond which is formed by the sharing of two electrons, in which both the electrons are donated by only one atom is known as coordinate covalent bond or dative bond.

In a compound having formula AB, the reaction for their combination is given as:

$A+:B\rightarrow A:B(A\leftarrow B)$

From the above equation, it is seen that B is donating its electrons to A. Thus,  A is electron deficient and B is electron rich. Thus, A is accepting a pair of electrons and is known as acceptor (or a metal in complex). B is donating its electrons. Thus, it is considered as donors (or a ligand in complex)

Hence, the substance is termed as ligand.