A student has been collecting silver coins and copper coins. One day she observed a black coating on silver coins and a green coating on copper coins. Which chemical phenomenon is responsible for these coatings? Write the names of black and green coatings.

Open in App

Solution

A). When silver reacts with hydrogen sulphide in presence of air (oxygen)
to form a silver sulphide in black colour
The equation is:-

$2 A g + H_{2} S ⟶ A g_{2} S + H_{2}$

B). The Copper forms a green deposit on its surface when exposed to moist air. This is usually basic copper (II) sulphate.

Suggest Corrections

Similar questions

Q. Rahul has been collecting copper coins and silver coins. One day he observed a green coating on copper coins and a black coating on silver coins. State the chemical phenomenon responsible for these coatings and also write chemical names of each coating.

A numismatist (coin collector) has been collecting gold coins, silver coins and copper coins for a long time. One day he observed a black coating on silver coins and green coating on copper coins. Which chemical process is responsible for these coatings?

Q. Three bags contain