Precipitation Reactions With Ammonia

Question 1

[Fe(H2O)6] 2+ with 2NH3 precipitation reaction forms what?

Answer 1

Forms [Fe(H2O)4(OH)2] + 2NH4+

Question 2

What type of reaction is the first step of 2NH3 + [Fe(H2O)6] 2+ ? And why?

Answer 2

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

Question 3

Colour change for [Fe(H2O)6] 2+ with 2NH3

Answer 3

Pale green solution forms a pale green precipitate of [Fe(H2O)4(OH)2]

Question 4

What colour does green precipitate of [Fe(H2O)4(OH)2] go on standing?

Answer 4

Brown

Question 5

[Fe(H2O)6] 3+ with 3NH3 forms what in the first step?

Answer 5

[Fe(H2O)3(OH)3] and 3NH4+

Question 6

What type of reaction is [Fe(H2O)6] 3+ with 3NH3 and why?

Answer 6

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

Question 7

Colour change for [Fe(H2O)6] 3+ with 3NH3

Answer 7

Yellow brown solution forms a brown precipitate of [Fe(H2O)3(OH)3]

Question 8

Is there any further reactions if more ammonia is added to [Fe(H2O)3(OH)3] or [Fe(H2O)4(OH)2]

Answer 8

No unlike with copper AND COBALT , the reaction stops here
So it is the same reaction more or less with hydroxide ions but ammonia acts as the base

Question 9

First step of [Co(H2O)6]2+ with 2NH3 forms what?

Answer 9

[Co(H2O)4(OH)2] + 2NH4+

Question 10

Colour change for [Co(H2O)6] 2+ with 2NH3

Answer 10

Pink solution to a blue precipitate

Question 11

What colour is precipitate of [Co(H2O)4(OH)2] ?

Answer 11

Blue

Question 12

What type of reaction is first step of [Co(H2O)6]2+ with 2NH3 and why?

Answer 12

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

Question 13

Ligand exchange reaction for [Co(H2O)4(OH)2] + 6NH3 forms what?

Answer 13

[Co(NH3)6]2+
4H2O
2OH-

Question 14

Colour change for formation of [Co(NH3)6]2+

Answer 14

Blue precipitate of [Co(H2O)4(OH)2] redissolves and forms a brown solution

Question 15

What colour is [Co(NH3)6]2+ ?

Answer 15

A brown solution

Question 16

What colour does [Co(NH3)6]2+ go on standing?

Answer 16

Yellow

Question 17

What transition metals can actually undergo substitution ligands with ammonia?

Answer 17

Cr 3+
Cu 2+
Co 2+

Question 18

Adding 6NH3 + [Cu(H2O)₄(OH)₂] forms what and what colour?

Answer 18

[Cu(ΝΗ3)4(Η2Ο)2] 2+
Dark blue