What is the coordination number of Ag in [Ag(CN)2]- ion?

The correct answer is option 3. 2.

Let us break down the coordination number of silver (Ag) in the complex ion \([Ag(CN)_2]^{-}\).

Structure and Ligands:

Complex Ion: \([Ag(CN)_2]^{-}\)

This ion consists of a silver ion (Ag\(^+\)) coordinated with two cyanide ions (CN\(^-\)).

Cyanide Ion (CN\(^-\)):

Cyanide ion (\(CN^-\)) acts as a ligand in this complex.

Each cyanide ion has a carbon atom (C) that donates a lone pair of electrons to the silver ion.

Coordination Number:The coordination number of a metal ion is the number of ligand donor atoms to which the metal ion is directly bonded.

In \([Ag(CN)_2]^{-}\):

Silver (Ag\(^+\)) is bonded to two cyanide ions (CN\(^-\)). Each cyanide ion provides one donor atom (carbon atom) to bond with the silver ion. Therefore, in \([Ag(CN)_2]^{-}\), the silver ion (Ag\(^+\)) is directly bonded to two cyanide ligands (CN\(^-\)).

The coordination number of silver (Ag) in \([Ag(CN)_2]^{-}\) is \(2\). This indicates that there are two cyanide ligands bonded to the central silver ion in the complex ion.