INSTANT SILVER TARNISH-DETARNISH Submitted by: H. I. Feinstein, George Mason University, Fairfax, Virginia 22030 Checked by: James Thompson, Hiram College, Hiram, Ohio 44234 PREPARATION
Solution A: About 10 ml of (NH&S* solution prepared according to any standard procedure.' Solution B: Instant silver cleaner? 8.0 g of thiourea, 5.1 g (or 4.3 ml) of 12 N HCI, 0.3 g of water-soluble perfume, 0.5 g of nonionic surfactant such as Triton X-100 or Micronex and enough H z 0 to make 100 g. Strip of silver foil or piece of tarnished silver.
REMARKS
-
The tarnishing reaction is ln.2Ag(s) + S;'-
Ag,S(s)
+ S2-
(1)
T h e cleaning reactions are9
DEMONSTRATION:
If a sample of tarnished silver is not available, dip a piece of silver foil in A for a minute or until a noticeable darkening of the silver occurs. Remove the metal and rinse thoroughly in water. Immerse the tarnished silver in B. The tarnish is removed. Rinse the metal immediately in running water and dry.
A34 / Journal of ChemicalEducstion
When the tarnished silver is immersed in the cleaner, reaction (21, (3) and (4) are displaced to the right. '"Handbook of Chemistry and Physics," The Chemical Ruhher Co., Cleveland. 2Brenner,Howard, ''Silver Dips," Soap and Sanitary Chemicals, 29, lfi3 (May, 1953).
