Home Test for Silver
Date: November 2007
I would like to do a test to see if flakes of metals found are
gold or silver. I found in your archives a home test for gold, but I did
not find a home test for silver. Do you know of any way to find out if a
flake of metal is silver?
level lab course at the University level. In recent years this has become
less popular, which is unfortunate in my opinion because it not only taught
lab skills, it gave the student a real "live look" at various inorganic
substances. But my regret is another topic.
If you have a science teacher who can assist you, it would be desirable to
obtain some nitric acid (HNO3). Silver is soluble in moderately concentrated
nitric acid so some or all of metal flakes will dissolve. Separate any
insoluble material from the solution by filtration, or centrifugation. If
any insoluble material is dense enough you may only have to let the solid
settle out under the force due to gravity. Add a few drops of hydrochloric
acid to the clear solution. The formation of a white precipitate is suggestive
of silver, but copper and lead have to be eliminated as possibilities, since
they also form insoluble chlorides. This is done by adding a few drops of
concentrated ammonia to solution/precipitate mixture.
Silver chloride is soluble in moderately concentrated ammonia, whereas copper
and lead chloride are not. The finding can be re-confirmed by re-neutralizing
the soluble ammonia / silver complex with excess hydrochloric acid. In which
case a white precipitate will reform.
These experiments use potentially harmful substances, e.g. nitric acid,
concentrated ammonia. You should seek guidance of a person knowledgeable in
the handling of chemicals to assist you. Of course, wear safety glasses, use
gloves, and follow good laboratory procedures. Below are some web sites where
you can find further info and details.
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Update: June 2012