Separating Cations: AgNO3 + NH3?

  • Thread starter Kitty808
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In summary, adding NaOH to the solids should get Fe(OH)3(s), Cr(OH)4(-1)(aq), and Ag(OH)(aq)? Centrifuging out the solid should leave the Ni(NH3)6(2+) which can be run the confirmatory test on. However, adding OH- to an ammonia solution of silver can produce dangerous compounds, so it's not advisable.
  • #1
Kitty808
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0
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.
 
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  • #2
I would separate Ag+ as chloride. Ag(NH3)2+ is not a solid.

But it seems like you are contradicting yourself in your post.
 
  • #3
Kitty808 said:
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 [tex]Fe(NO_3)_3,\ Cr(NO_3)_3? [/tex] Otherwise they can't then give [tex]Fe(OH)_3,\ Cr(OH)_3[/tex] 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 [tex]Ag(NH_3)_2^+[/tex], 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.

[tex]2Ag(NH_3)_2^+\ +\ 2NaOH\ \rightarrow\ Ag_2O\ +\ 2Na^+\ +\ 4NH_3\ +\ H_2O[/tex]

(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.
 
Last edited:
  • #4
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.
 
  • #5
Go net ionic. Ag+ is getting complexed by two ammonia molecules.

Please don't necropost, rather start a new thread.
 
  • #6
Will do, thanks.
 

What is the purpose of separating cations using AgNO3 and NH3?

The purpose of this experiment is to separate and identify different cations present in a solution based on their unique chemical reactions with AgNO3 and NH3.

What cations can be separated using AgNO3 and NH3?

AgNO3 and NH3 are commonly used to separate cations such as silver (Ag+), copper (Cu2+), lead (Pb2+), and mercury (Hg2+) from other cations in a solution.

What is the chemical equation for the reaction between AgNO3 and NH3?

The chemical equation for the reaction between AgNO3 and NH3 is: AgNO3 + 2NH3 → [Ag(NH3)2]+ + NO3-

How do you know when the reaction between AgNO3 and NH3 is complete?

The reaction between AgNO3 and NH3 is complete when all of the cations have reacted with either Ag+ or NH3, leaving only the anions in the solution. This can be determined by observing a color change in the solution or by performing a confirmatory test for each specific cation.

What are some potential sources of error when separating cations using AgNO3 and NH3?

Potential sources of error include contamination of the solutions, incomplete reactions, and human error in conducting the experiment. It is important to carefully follow the experimental procedure and use clean equipment to minimize these errors.

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