Question

The color of copper carbonate is
A. Black
B. Green
C. White
D. Blue

Answer 1

Hint- In order to find the colour of copper carbonate, first we will see the basic state or chemical state in which copper carbonate stays. On the basis of its reaction with air present in the atmosphere and the chemical abundance of copper carbonate, we will find the colour of copper carbonate.

Complete answer:
Copper carbonate is a rarely seen moisture-sensitive compound. Basic copper carbonate (the "copper carbonate" of commerce) is actually a copper carbonate hydroxide.
Copper metal turns gray in colour when exposed to dust due to corrosion. Once copper is exposed to sunlight, the metal reacts to form a combination of copper carbonate and copper hydroxide with moisture and natural gases. After some time copper becomes green due to its exposure to air.
Copper carbonate always stays as copper carbonate hydroxide in the atmosphere.
Oxidation of Copper and Changing of Color
The copper powder reacts with oxygen, forming an opaque coating of copper oxide that tends to be green or bluish-grey in color. This layer is termed the patina.
Hence, the colour of copper carbonate is green.

So, the correct answer is option B.

Note- Oxidation is a phenomenon that causes one element to lose electrons (and/or hydrogen) when interacting with another. Similar to iron and aluminium, if exposed to air, the copper element undergoes the oxidation process. If the atmosphere contains high moisture content then this cycle would be easier. The oxidised copper layer is patina. The patina serves as a shielding shield as opposed to other harmful oxidation processes and it does not induce any degradation in the metal. Thus, copper is regarded as an important corrosion resistant element. The patina avoids further copper degradation below the oxidised base.