What is the reason for tarnishing of silver ?
Answers
Answer:
Sterling silver is an alloy of silver and base metals such as copper; the copper reacts with sulphur-containing gases in the air to form a layer of the compound copper sulphide (Cu2S). Pure silver is less prone to tarnish, but will still react to form silver sulphide (Ag2S).
The colour of tarnish on silver changes as tarnishing proceeds. This is due to a phenomenon called “thin film interference.” As light hits the thin film of tarnish on the silver, it splits; some of it reflects off the top surface, and some of it reflects off the silver under the tarnish. When the light from the top and the bottom of the tarnish recombines, some of the colours are lost through interference. The colour that remains depends on the thickness of the tarnish layer. In the early stages of tarnishing, as the thickness grows from 10 to 100 nanometres (nm), the colour changes from yellow through red-brown to blue. For thicknesses greater than about 100 nm, the colour is black, the true colour of silver sulphide.
Answer:
Tarnish is a product of chemical reaction that is caused by the other metals that are mixed with silver reacting to moisture and sulfur in the air. Sterling Silver will generally tarnish quicker in high humidity climates and places with high levels of air pollution.
Explanation:
Sterling silver is an alloy of silver and base metals such as copper; the copper reacts with sulphur-containing gases in the air to form a layer of the compound copper sulphide (Cu2S). Pure silver is less prone to tarnish, but will still react to form silver sulphide (Ag2S).