Precipitation Reactions With Ammonia Flashcards
[Fe(H2O)6] 2+ with 2NH3 precipitation reaction forms what? step 1
Forms [Fe(H2O)4(OH)2] + 2NH4+
What type of reaction is the first step of 2NH3 + [Fe(H2O)6] 2+ ? And why?
Acid base reaction
Because 2 NH3 acts as a base and accepts 2H+ from 2 water ligands =NH4+
And the 2 water ligands that acted as an acid and donated H+ will become OH ligands
Colour change for [Fe(H2O)6] 2+ with 2NH3
Pale green solution forms a pale green precipitate of [Fe(H2O)4(OH)2]
What colour does green precipitate of [Fe(H2O)4(OH)2] go on standing?
Brown
[Fe(H2O)6] 3+ with 3NH3 forms what in the first step?
[Fe(H2O)3(OH)3] and 3NH4+
What type of reaction is [Fe(H2O)6] 3+ with 3NH3 and why?
Acid base reaction
Because 3 NH3 acted as base and accepted H+ from 3 water ligands to form 3NH4+
And the 3 water ligands that acted as an acid by donating H+ become OH ligands
Colour change for [Fe(H2O)6] 3+ with 3NH3
Yellow brown solution forms a brown precipitate of [Fe(H2O)3(OH)3]
Is there any further reactions if more ammonia is added to [Fe(H2O)3(OH)3] or [Fe(H2O)4(OH)2]
No unlike with copper, the reaction stops here
So it is the same reaction more or less with hydroxide ions but ammonia acts as the base
First step of [Co(H2O)6]2+ with 2NH3 forms what?
[Co(H2O)4(OH)2] + 2NH4+
Colour change for [Co(H2O)6] 2+ with 2NH3
Pink solution to a blue precipitate
What colour is precipitate of [Co(H2O)4(OH)2] ?
Blue
What type of reaction is first step of [Co(H2O)6]2+ with 2NH3 and why?
An acid base reaction because 2 NH3 acts as a base to accept 2H+ from 2 water ligands to form NH4+
And the 2 water ligands that acted as an acid that donated H+ becomes OH ligands
Ligand exchange reaction for [Co(H2O)4(OH)2] + 6NH3 forms what?
[Co(NH3)6]2+
4H2O
2OH-
Colour change for formation of [Co(NH3)6]2+
Blue precipitate of [Co(H2O)4(OH)2] redissolves and forms a brown solution
What colour is [Co(NH3)6]2+ ?
A brown solution
What colour does [Co(NH3)6]2+ go on standing?
Yellow
