Posted 3 Weeks Ago by Orcus
Neither.
See post 15 for the correct equation you need.
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Posted 3 Weeks Ago by Orcus
or post 10
You don't seem to have got your head around the formation of a complex.
silver chloride is insoluble in water.
But add ammonia (ammonium hydroxide - same thing in water solution) and the Ag+ ions 'complex' with two ammonia molecules each to form a 'complex' ion. Ag[NH3]2+
You really need to put this in the equation for it to describe what you observe.
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Posted 3 Weeks Ago by  Clive the flying ostrich - Thingite Warlord Emeritus
>>You don't seem to have got your head around the formation of a complex.<<
Correct. 
It's why I come here for help.
I was having another bash at solving this on my own.
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Posted 3 Weeks Ago by Orcus
Just thought I'd post it in again as it didn't seem to get through is all.
The complex salt Ag[NH3]2+ Cl- *is* soluble - and it is not the same species as simply Ag+ and ammonia floating about in solution individually.
H3N-Ag-NH3 is essntially a charged molecule with discrete covalent bonds between the silver atom and the ammonia molecules.
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Posted 3 Weeks Ago by Clive the flying ostrich - Thingite Warlord Emeritus
Thanks for your help Orcus.
I'll be honest I am completely confused by this now.
I've looked at your solution in the posts your recommended and I'm trying to work it back wards to see how you resolved the balancing.
The only way I can figure it (bearing in mind this process assumes you have the correct answer with which to balance) is if you knew that you would have to form water as part of the solution.
Because if that was the case, it would be obvious that you'd be deficient one hydrogen and therefore need to multiply the amount of ammonium hydroxide to account for this.
Is that right - that H20 is something I should have expected to form?
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Posted 3 Weeks Ago by Orcus
Well you could as easily write
AgCl(s) + 2NH3(aq) ----> Ag[NH3]2Cl(aq)
But NH3(aq) exists in the form of ammonium hydroxide.
It's an acid-base reaction. NH3 accepts a proton from water to give NH4+ and at the same time water loses that proton to become OH-
Hence NH3(aq) = NH4OH in aqueous solution.
(NH3 + H2O ----> NH4OH)
So if you use NH4OH as the form of ammonia in the equation then you lose a water molecule to give NH3 and H2O in order for the Ag+ ions to accept NH3.
Acid base reactions are always in equilibrium though so it would be more correct to write
NH3 + H2O <======> NH4OH
(sorry can't do the correct arrow for an equilibrium in this format)
So that at least explains where the water came from. But you could just omit it and use NH3 instead.
What you really need to know already is that ammonia and Ag+ form a complex. And also that ammonia is a base.
So you do need to know a bit about the chemical properties of the ions/molecules involved in this reaction.
Water is always easily formed or accepted in aqueous reactions. It's the removal or acceptance of protons to an from it that remove/generate the 'spare' water that appeared in my formula.
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Posted 3 Weeks Ago by Clive the flying ostrich - Thingite Warlord Emeritus
Thanks that does help. So basically I *should* anticipate the water in equation because the ammonium is already i the relationship with the water when it goes in (like you said - borrowing ions to be either NH3 or Nh4OH +/- H2O)
Do you mind if I try your patience with any others later on? 
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Posted 3 Weeks Ago by Orcus
No problem 
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