Why sometimes silver turns black?
After 1 year my silver necklace turned black in some parts of it.My sister got herself a silver necklace 2 and after 2 weeks it turned black and ugly.The only chemical reaction i can think up is
Ag+NaCl that could cause this or maybe not,maybe it’s another chemical reaction,maybe it’s a physical reaction.Thank you in advanced.
Top 4 Answers
Favorite Answer
Silver turns dark gray or black as it oxidizes. You can get rid of the discoloration by using a dip-polish method. You can do this at home, safely, with things found in your kitchen (salt, baking soda and aluminum foil).
0
4 years ago
Sterling silver is an somewhat complicated substance. finding on the standard and acid unfastened coating it is going to in many cases discolour. do no longer enable this alarm you as meaning that’s of solid high quality in simple terms like gram ma’s silver tea set. once you have been silver that’s relatively reactive to the secretion of salt on your actual fluids. to help end this yet some toddler powder on the necklace or your neck. this could help some what; additionally shop silver in a closed case because of the fact the oxygen is the air additionally impacts the tarnishing. to maintain sparkling in simple terms a small little bit of vinegar or Windex i discover to be the main powerful.
0
Silver corrodes very very slowly. It is almost at the very bottom of the Reactivity Series of Metals. What I believe is that your necklace is just COATED with silver. When the silver layer is brushed off due to friction or abrasion, the inside layer (probably containing copper) will start to oxidize. The black layer is CuO (Copper Oxide).
FYI, AgCl is not black.
0
You are describing the reaction evident in metal, in this case silver, when oxidisation or corrosion occurs. This is usual when Metal is exposed to air over a period of time. The term for this effect, in the case of silver, is ‘tarnish’.
“The silver was tarnished by long exposure to the air”.
0
