chucknorris - 10-12-2012 at 00:20
I know that one can release the silver from nitrate salts with copper tube, but does this apply to other salts too, including those that are higher
than copper at the periodic table?
woelen - 10-12-2012 at 01:22
Your question is not really clear. Do you mean other salts of silver, or in general salts of other metals.
Silver can also be displaced from other silver salts by copper, but the salt must be soluble in water. Many silver salts are not or only very
sparingly so. This means that in practice it does not work for most other common silver salts, such as the chloride, bromide, iodide, phosphate and
carbonate. Silver sulfate is somewhat soluble, so for this it works, but only very slowly, due to the dilute nature of solutions of silver sulfate.
smaerd - 10-12-2012 at 06:15
Yea as woelen says silver halide salts are actually pretty covalent in nature because of them being highly charged transition metal cations with
easily polarized anions(See Fajans rules).edit - to clarify covalent generally lends to poor solubility in water and a greater solubility in organic
solvents. Nitrates salts tend to be soluble in water.
The example of the reaction in the OP is a redox reaction, rather then a metathesis reaction. So if you are curious about similar oxidation/reduction
reactions it would be a good idea to review some information about that. Sometimes these can be predicted by using charts such as this:
[Edited on 10-12-2012 by smaerd]
neptunium - 10-12-2012 at 06:18
check the red/ox table if its higher than silver then it wont work but silver is pretty high and a lot of metals will work fine (Zn, Al, Fe etc...)
neptunium - 10-12-2012 at 06:20
damn! we posted the same thing at the same time didnt we? yours is better tho!
unionised - 10-12-2012 at 13:41
If you mix any silver salt with an excess of sodium hydroxide then heat it till it melts the silver is converted to the metal.
In general you also get oxygen, water, and the sodium salt of whatever silver salt you started with so, for example, silver chloride gives sodium
chloride, water and oxygen.
Of course, molten sodium hydroxide isn't nice stuff to work with.
Borax will work in most cases too.
phlogiston - 11-12-2012 at 06:10
Copper is often used in precious metal refining because it is only able to reduce metals that are more 'noble', which includes silver, gold and
platinum but not many 'base metals' such as iron, nickel, lead, zinc, etc.
Therefore, it is a convenient way to specifically recover the valuable metals from a solution.
If you use a 'less noble' metal in place of copper (a stronger reductor), many base metals would also come out of solution. For example, if you take
zinc, it will still be able to precipitate silver, but also for instance lead, nickel, and copper (and others).
As mentioned, study electrochemistry and the mechanisms behind it (electron transfer / redox reactions) will become clear.