Sciencemadness Discussion Board

Silver Nitrate - anything interesting?

hodges - 26-1-2004 at 16:17

Back when I was in high school I remember wanting to get some silver nitrate. Now I can't remember what for. I recently found a place to buy it for around $10 an ounce, but a search on the internet did not reveal too many hobby uses. The only thing I can think of is maybe I was interested in making photosensive stuff. In my searching I did stumble across some explosive compounds that can be made with silver nitrate, but I'm sure thats not what I wanted it for back then and I'm really not interested in experimenting with high explosives now either. But are there any other interesting reactions?

Hodges

vulture - 27-1-2004 at 08:34

A nice reaction is to coat the inside of a flask with a silver coating.

This can be done with silvernitrate and dextrose. I'll post the procedure if you're interested.

JustMe - 27-1-2004 at 11:32

Lots of "interesting" stuff can be done with Silver Nitrate.

The "classic" high school experiment involves displacing the silver ions with copper, while growing stalactites of silver. The idea is to put an open "coil" of copper wire (or a copper strip) in a solution of silver nitrate. Silver stalactites grow on the copper and the solution turns blue from the copper ions. When you're done you can collect the silver. Just make sure you use distilled water!

Just be careful with the solid or solution, they are caustic to the skin, and potentially blinding to the eyes.

chemoleo - 27-1-2004 at 12:21

In fact this sounds like a nice way of purifying impure silver alloys - dissolve in HNO3 and do the reaction with Cu - only metals more electropositive than Cu will react with the Cu! and there aren't many, particularly in things such as silver forks etc :)

[Edited on 27-1-2004 by chemoleo]

another nice way

Polverone - 27-1-2004 at 19:17

Dissolve your impure silver (jewelry, forks, coins, etc.) in HNO3. Dry to remove excess acid (as far as practical). Then add aqueous ammonia until all solids dissolve (if some stubbornly refuses to dissolve, it's not from silver; filter it out). Then add ammonium ascorbate solution, easily made from aqueous ammonia and food-grade ascorbic acid. It will rapidly reduce the complexed silver to metallic silver, forming a curdy precipitate. Other metals, less easily reduced (like copper) remain complexed (so they aren't precipitated as the ascorbate salt) and aren't rapidly reduced in the cold. Metallic silver is the only solid produced, and can be removed by filtration.

I imagine that other complex-forming materials (such as KCN solution) could be used as well, but aqueous ammonia is inexpensive and relatively safe.

hodges - 27-4-2004 at 14:30

Can regular (grocery store) sugar be used in a silvering reaction with silver nitrate? Most of the procedures I have found call for glucose, which I don't have.

Obviously silver is reduced during a silvering process. But does anyone know the equations? I've not been able to find them in any of the silvering procedures. What happens to the NH3 part of the complex ion?

Proteios - 27-4-2004 at 14:48

makes any skin that it comes in contact with go deep brown/black (due to colloidal Ag ppt in the skin).

Precipitates with pretty much all anion, most notably Cl (very useful)

Electrolysis of AgNO3 is also v. interesting. The manner of Ag deposition depends upon the voltage used (dendritic or spongey)..... plus it has different colours when voltage is being applied (black i think), then instantly goes grey when the voltage is removed.

Coating things with silver by electrolysis is a total black art! Getting Ag out of solution is easy.. getting it to adhere to a surface is not!

silver mirror test for aldehydes (Tollen's Test)

Magpie - 27-4-2004 at 20:06

Hodges:

See the University of Regensburg video chemistry site delivered to us by Hermes.
It gives the reactions and a video demonstration - pretty neat.

Hunsdieker

Turel - 27-4-2004 at 20:56

Hunsdieker Reaction

[Edited on 28-4-2004 by Turel]

Esplosivo - 28-4-2004 at 03:28

If you're interested in energetics you can produce Silver Carbide by bubbling ethyne through silver nitrate dissolved in ammonia. Be careful though.

Quote:

Can regular (grocery store) sugar be used in a silvering reaction with silver nitrate? Most of the procedures I have found call for glucose, which I don't have.


Sucrose is not a reducing agent and cannot be used for what you called the 'silvering reaction'.

[Edited on 28-4-2004 by Esplosivo]