Question

explain the corrosion process of object made of iron Copper and silver

Answer 1

Copper, silver and gold are found in elemental or "native" form at the earth's surface. The best nuggets have been picked up already, since the land has been scoured for them wherever there are people who appreciate them. They are called the currency metals, since they have been used in coins since the beginning of money. The three largest U.S. coins in each of the metals are shown at the right. The large cent was issued 1793-1857, and weighs 11g. The Peace Dollar was minted 1921-1935, and weighs 27g. The St. Gaudens Double Eagle, $20, was minted 1907-1933, and weighs 34 g. At today's prices, the metal in these coins is worth $0.02, $4.27 and $405.61. Now, however, copper alloys predominate in the miserable debased coins of no artistic merit we use every day. They are also called noble metals, and all others base metals. They are the royal family of the periodic table, family IB. Their alchemical symbols are the signs of the three brightest planets, the sun, the moon and Venus, their colors yellow, white and red.

All three are not only delightful in appearance and resistant to corrosion, but can be hammered into ornaments of artistic distinction. The three are ductile, capable of being drawn into fine wires, and malleable, capable of being hammered into thin sheets. Gold, indeed, is outstandingly ductile and malleable, able to be drawn into wires thinner than a hair and beaten into sheets thin enough to transmit light. All three metals are important in technology, especially in electronics.

Answer 2

Copper will become greenish in colour due to the formation of copper carbonate.Silver articles becomes black in colour due to the formation of silver sulphide