Question

On reaction with AgCl with an ammonia solution we get a complex whose central atom has _________________ number of ligands.

Answer 1

Hint:Ligands are defined as the ions or the neutral molecule that is bonded to the central metal atom. In the complex the ligand act as a Lewis base known as electron pair donor, while the central metal atom is known as Lewis acid called electron pair acceptor. It forms the covalent bond with the central metal atom. The word ligand means tie or bind.

Complete answer:
There are different types of ligand such as monodentate ligand in which the ligand is attached to the metal atom at one place only. Such as \[\rm{B{{r}^{-}},C{{l}^{-}},O{{H}^{-}}}\]. The other is bidentate ligand ,it is lewis base which donates two electrons to the central metal atom. For example- ethylenediamine, acetylacetonate, etc. When chelating ligands are present in the complex it is called chelates. When three lone pairs of electrons are donated to the central metal atom then it is called tridentate ligand. For example- triethylenetetramine. Ambidentate ligand is a ligand in which more than one potential donor atom is present. For example: \[\rm{NC{{S}^{-}}}\].
When silver chloride reacts with ammonia in the presence of soluble chlorides such as hydrochloric acid , it forms a white precipitate. The formed precipitate is insoluble in acid such as \[\rm{HN{{O}_{3}}}\] but it dissolves in ammonia thus forming a complex . The equation for the reaction is,
\[\rm{AgCl+2N{{H}_{3}}\to {{[Ag{{(N{{H}_{3}})}_{2}}]}^{+}}+C{{l}^{-}}}\]
So here in the product, the complex formed has two ligands and they are two ammonia molecules.

So the answer of the blank is two.

Note:
The complex diamminesilver(I) ion is stable in nature and the position of equilibrium lies well to the right. The silver chloride will dissolve in concentrated ammonia by Le Chatelier principle. Ions are not the precipitates, as all bulk matter must be approximately electrically neutral, so the silver chloride dissolves in excess of concentrated ammonia.