Separating Cations: AgNO3 + NH3?

[Kitty808]

Ok, lab work...
I have to figure out a way to separate out the individual cations from a solution containing Fe(NO3)2, Cr(NO3)2, Ag(NO3), and Ni(NO3)2 and get each one into a particular form and perform a confirmatory test on it.
I've think I know how to get started on it. First adding some NH3 to the solution I should have Ni(NH3)6(2+) (aq), Fe(OH)3(s), Cr(OH)3(s), and Ag(NH3)2(s). Centrifuging out the solid should leave the Ni(NH3)6(2+) which I can run the confirmatory test on.

This is where I get a little stuck. I think by adding NaOH to the solids I should get Fe(OH)3(s), Cr(OH)4(-1)(aq), and Ag(OH)(aq)? I'm not sure about the Ag(OH) if that is correct and whether it is aq or s.

If I did my reaction right its:
Ag(NH3)2(+) + NaOH --> Ag(OH) + Na(NH3)?

If I could get some input as to whether I'm on the right track or not it would be appreciated very much.

 

[Borek]

I would separate Ag⁺ as chloride. Ag(NH₃)₂⁺ is not a solid.

But it seems like you are contradicting yourself in your post.

 

[lightarrow]

Ok, lab work...
I have to figure out a way to separate out the individual cations from a solution containing Fe(NO3)2, Cr(NO3)2

Maybe you intended Fe(NO_3)_3,\ Cr(NO_3)_3? Otherwise they can't then give Fe(OH)_3,\ Cr(OH)_3 as you write after

, Ag(NO3), and Ni(NO3)2 and get each one into a particular form and perform a confirmatory test on it.
I've think I know how to get started on it. First adding some NH3 to the solution I should have Ni(NH3)6(2+) (aq), Fe(OH)3(s), Cr(OH)3(s), and Ag(NH3)2(s). Centrifuging out the solid should leave the Ni(NH3)6(2+) which I can run the confirmatory test on.

And Ag(NH_3)_2^+, as Borek wrote.

This is where I get a little stuck. I think by adding NaOH to the solids I should get Fe(OH)3(s), Cr(OH)4(-1)(aq), and Ag(OH)(aq)? I'm not sure about the Ag(OH) if that is correct and whether it is aq or s.

If I did my reaction right its:
Ag(NH3)2(+) + NaOH --> Ag(OH) + Na(NH3)?

No.

2Ag(NH_3)_2^+\ +\ 2NaOH\ \rightarrow\ Ag_2O\ +\ 2Na^+\ +\ 4NH_3\ +\ H_2O

(Initially it forms AgOH, which quickly decomposes into the oxide).

Anyway, adding OH- to an ammonia solution of silver can produce dangerous compounds, so it's not advisable.

 

[nanogeek]

Borek,

First off I am into learning on my own, but I am stuck here and could use a little help.

I am working on equation writing, I have NH3(aq) + AgNO3. I have hit the Raymond Chang, Ninth edition for explanation on solving this, but I might be in the wrong section for comprehension. Could you guide me in the direction of information that could help me solve this, Thanks.

 

[Borek]

Go net ionic. Ag⁺ is getting complexed by two ammonia molecules.

Please don't necropost, rather start a new thread.

 

[nanogeek]

Will do, thanks.