22. A student has been collecting silver coins and and Copper Coins. O

1.	22. A student has been collecting silver coins and and Copper Coins. One day he obscrvead ablack coating on Silver Coins and green Coating on Copper Coins. Give the Chenical Nanmcof black nd green Coating. How are they formed
Answer» Black coating on silver coins is due to silver sulphide(Ag2s). 2 Ag(s) + H2S(g) ----- Ag2S(s) + H2(g).Green Coating on copper coins is due to copper carbonate and copper hydroxide. 2 Cu + H2O + CO2 + O2 ------ > Cu(OH)2 + CuCO3

22. A student has been collecting silver coins and and Copper Coins. One day he obscrvead ablack coating on Silver Coins and green Coating on Copper Coins. Give the Chenical Nanmcof black nd green Coating. How are they formed

Answer»

Black coating on silver coins is due to silver sulphide(Ag2s).

2 Ag(s) + H2S(g) ----- Ag2S(s) + H2(g).Green Coating on copper coins is due to copper carbonate and copper hydroxide.

2 Cu + H2O + CO2 + O2 ------ > Cu(OH)2 + CuCO3