Question

Ammonia is a good complexing agent. Explain.

Answer 1

1. The lone pair of electrons on the nitrogen atom facilitates the complexation of ammonia with transition metal ions. Thus, ammonia is a good complexing agent as it forms a complex by donating its lone pair of electrons.
   a. \[\ce{\underset{\text{(Blue)}}{Cu^2+_{ (aq)}} + 4NH_{3(aq)}->\underset{\text{(Deep blue)}}{[Cu(NH3)4]^2+_{( aq)}}}\]
   b. \[\ce{\underset{\text{(White)}}{AgCl_{(s)}} + 2NH_{3(aq)}->\underset{\text{(Colourless)}}{[Ag(NH3)2]Cl_{( aq)}}}\]
2. This reaction is used for the detection of metal ions such as Cu²⁺ and Ag⁺.