Why does eating eggs with a silver spoon make the spoon black? The discoloration of the silver spoon is due to oxidation. One of the important factors is that there is a great affinity between silver ions and sulfur ions, which is easy to produce chemical reactions. As a result of the reaction, silver sulfide appeared on the surface of silver. Because silver sulfide is gray-black, with the increase of silver sulfide, the surface color of silver gradually changes from white to yellow, then to gray and finally to black. The amount of this chemical change is very small. As long as silver meets hydrogen sulfide or sulfur ions in the air in trillions to hundreds of trillions, chemical reactions will occur.

Chicken soup also contains sulfur. Contact with silver products will make silver discolor, especially hydrogen sulfide produced by sewage and garbage discharge in urban air, so it is not surprising that silver discolors. When silver is oxidized or vulcanized, it also turns black. Under the conditions of high temperature and oxygen, silver is easily oxidized into silver oxide. In the sharp part of silver, its oxidation rate is faster than other parts. The main component of egg white is protein, which contains a lot of sulfur and reacts with silver hair to generate silver sulfide.

Generally speaking, sulfur or sulfide in egg white reacts slowly with silver. However, if something goes wrong in protein, for example, if the eggs are left for a long time, the organic sulfur in protein will be converted into sulfide, which will speed up the reaction. Egg yolk contains less sulfur. So the silver spoon will turn black when eating custard. The main chemical components of eggs are water and protein, while protein contains elements such as sulfur, phosphorus and iron. It reacts with silver and sulfur to produce silver sulfide (black with metallic luster). The yellow color of silver is due to the initial reaction. After a period of time, the surface of silver will turn black, probably because there are many children, so don't eat eggs with any silver spoon. Silver objects turn black when they touch these things. "Silver needle poisoning experiment" is similar to the black egg principle when silver jewelry is used.

Arsenic is an ancient poison, which is mainly composed of arsenic trioxide. Due to the backward refining process, the purity of arsenic is very low, with a small amount of sulfur impurities. Sulfur will react with silver to form silver sulfide, so the needle will turn black immediately.