Silver Tarnish: A Redox Reaction

Made by Dirk, Jane, Lois, Fox, Liz

Silver & Silver TarnishSilver is a beautiful metal. Its shine, beauty, luster and attractiveness cannot be replicated by any other metal. It is used extensively globally for making various items, from jewelry to decorative items to even silverware for home use. Over the ages, silver and gold have gained so much importance that they have become objects of desire.

Over a period of time, you see its beauty diminishing. You see the discoloration of you silver article and feel disheartened and distraught. This discoloration, called silver tarnish, is a hindrance. Silver gets very easily tarnished.

How can silver tarnish?

• O2(g) + 4Ag(s) + 2H2S(s)2Ag2S(s) + 2H2O(l)

Tarnish is formed on the surface of a silver object when silver reacts with H2S in the air. The product, black silver sulfide, forms the coating of tarnish on the silver.

Things you will need a tarnished piece of silvera pan or dish large enough to completely immerse the silver inaluminum foil to cover the bottom of the panenough water to fill the pana vessel in which to heat the waterhot pads or kitchen mitts with which to handle the heated water vessel

baking soda, about 1 cup per gallon of water

Cleaning Tarnished Silver• Start with plain soap

and water. The first thing to do is to wash your silverware or silver jewelry with soap and water to remove any dust or oils from the surface. You'll be removing the tarnish by way of a mild chemical reaction, and want to wash away anything that might block the tarnish from reacting.

Cleaning Tarnished Silver

• Prepare your equipment. The next step is to line a pan with aluminum foil and add enough water to completely cover the piece of silver you want to clean. I used a relatively small pan because I was cleaning jewelry, but this method works just as well for bigger pieces like platters or kettles, as long as you have a large pot that will hold enough water to entirely submerge the piece.

• Stir baking soda into the water in the pan. A couple of tablespoons will suffice for small items in a small pan, but you may need as much as a cup or two for large items in a gallon or more of water. As the baking soda dissolves, turn on the burner underneath the pan and let the water come to a boil.

Cleaning Tarnished Silver

• Add tarnished silver. As soon as the water starts to boil, you can remove the pan from the heat and submerge the silver in the hot water. Make sure the silver is in direct contact with the aluminum foil. The whole process can take several minutes, but it shouldn’t be long before you start to see tiny yellow or black flakes in the water, or notice that the aluminum foil is turning black. What’s happening is that the hot solution of baking soda and water is separating the sulfur from the silver and transferring it to the aluminum. This easy homemade tarnish remover takes advantage of the fact that sulfur is more chemically attracted to aluminum than silver.

Cleaning Tarnished Silver

• Use tongs to move the silver pieces around in the pan. You can even take it out of the solution briefly to get a better look at your progress. Just be gentle and avoid scratching the silver. Once the silver is clean, you should rinse it in clean water to remove any traces of baking soda, then dry it with a soft clean cloth. You may find that you can take off even more tarnish by rubbing at any remaining dark spots with the cloth.

Cleaning Tarnished Silver

Cleaning Tarnished Silver

You will be surprised to find……

Cleaning Tarnished Silver

• 2Al (s) + 6Ag(s) + 3S(s) +6H2O(l)6Ag (s) + 2Al (aq) + 6OH + 3H2S(g)

+ 2- 00

3+ -

This reaction is essentially the reverse of the reaction that forms tarnish. Here, silver ions in the Ag2S tarnish are reduced to silver atoms, while aluminum atoms in the foil are oxidized to aluminum ions. The tarnish-removing solution usually includes baking soda to help remove any aluminum oxide coating that forms and to make the cleaning solution more conductive.

Cleaning Tarnished Silver

Thank you!!!