The following reaction describes the process of removing silver tarnish, Ag2S(s), by soaking the item in a hot baking soda solution in which the container is lined with aluminum foil. 3Ag2S + 2 Al(s) + 3H2O(l) 6Ag(s) + Al2O3(s) + 3H2S(aq)
The baking soda acts to remove impurities on the surface of the aluminum foil and to improve the conductivity of the solution.
Identify the substance that is oxidized.
Identify the substance that is reduced.