Question

Ammonia is a good complexing agent. Give reasons.
Or Ammonia acts as a ligand. Explain.

Answer 1

Due to the presence of a lone pair of electrons on N, `NH_(3)` acts as a complexing agent (ligand). As a result, it combines with transition metal cations to form complexes. For example :
`underset("Silver chloride")(AgCl)+2NH_(3)tounderset("Diamminesilver (I) chloride")([Ag(NH_(3))_(2)]Cl),underset("Copper sulphate")(CuSO_(4))+4NH_(3)tounderset("Tetraamminecopper (II) sulphate")([Cu(NH_(3))_(4)]SO_(4)),underset("Chromium chloride")(CrCl_(3))+6NH_(3)tounderset("Hexaamminechromium (III) chloride")([Cr(NH_(3))_(6)]Cl_(3))`