Ligand Substitution

Question 1

Cu2+ with water

Answer 1

[Cu(H2O)6]2+

light blue solution

Question 2

[Cu(H2O)6]2+ with drop wise ammonia

Answer 2

NH4 1+ (blue precipitate as doesn’t dissolve)
[Cu(H2O)4(OH)2]
not a ligand as the same oxygens are still attached

Question 3

[Cu(H2O)6]2+ with conc ammonia

Answer 3

[Cu(NH3)4(H2O)2]2+

deep blue solution

Question 4

[Cu(H2O)6]2+ with conc HCl

Answer 4

[Cu(Cl)4]2-

yellow solution appears green as both ions are present

Question 5

Co2+ with water

Answer 5

[Co(H2O)6]2+

pink solution

Question 6

[Co(H2O)6]2+ with drop wise ammonia

Answer 6

[Co(H2O)4(OH)2]

green precipitate

Question 7

[Co(H2O)6]2+ with conc ammonia

Answer 7

[Co(NH3)6]2+
yellow
appears brown to other ions with different ligands in mixture
oxidation leads to brown-red solution

Question 8

[Co(H2O)6]2+ with conc HCl

Answer 8

[Co(Cl)4]2-
blue solution
adding H2O shifts equilibrium and makes paler

Question 9

Cr3+ with water

Answer 9

[Cr(H2O)6]3+

pale purple/violet solution

Question 10

[Cr(H2O)6]3+with drop wise ammonia

Answer 10

[Cr(OH)3(H2O)3]

green-grey precipitate

Question 11

[Cr(H2O)6]3+with conc ammonia

Answer 11

[Cr(NH3)6]3+

purple solution

Question 12

Cr2(SO4)3 and water

Answer 12

[Cr(H2O)5(SO4)]+

green solution