Ligand Substitution revision
• Explain the following ( use equations!)
• A) When 1,2 diaminomethane(en) is added to
the light blue aqueous copper(II) sulfate
solution, the colour of the solution intensifies
to dark blue.
• B) When dilute HCl(aq) is added to the dark
blue solution formed as a result of the
experiment in part A), the colour returns to
light blue.
Extra
• Suggest explanations for each of the following:
• A) When conc HCl is added to aqueous cobalt(II)
chloride solution , the colour of the solution
changes from pink to blue
• B)If water is added to some of the blue solution
in part A), the colour changes back to pink.
• C) If aqueous silver nitrate is added to some o the
blue solution from A) the solution changes to
pink again and a precipitate is formed
• A) [Cu(H2O)6]2+(aq)+ 3en(aq) →[Cu(en)3]2+(aq) + 6H2O(l)
• B) The reverse reaction of A) occurs, ligand
substitution with Cl- only occurs with conc HCl
Extra
• A) [Co(H2O)6]2+ (aq) + 4Cl-(aq)
• Octahedral
→
[CoCl4 ]2- (aq) + 6H2O(l)
Tetrahedral
• Pink
blue
• B) reverse reactions of A)
• C) Water replaces Cl- to reform [Co(H2O)6]2+
(aq)
•
Cl- + Ag+ → AgCl(s) white ppt