Question

Copper when heated strongly in air forms a black coloured compound X while copper

when kept in the air for prolonged time develops a green coating.

I) Identify X and write its chemical formula.

II) Name and define the process that develops the green coating on copper​

Answer 1

Explanation:

When a copper vessel is exposed to moist air for a long time it develops a green layer on its surface. Copper corrodes by oxidation in which it reacts with oxygen in the air to form copper oxide. 

Copper oxide then combines with carbon dioxide to make copper carbonate, which gives it a green colour. This process is called corrosion of copper.

The green material is a mixture of copper hydroxide (Cu(OH)2) and copper carbonate (CuCO3). The following is the reaction:

2Cu(s)+H2O(g)+CO2+O2→Cu(OH)2+CuCO3(s)

Copper(II) carbonate is a blue-green compound.

Answer 2

Answer:

1 the black coloured substance is copperoxide

ie CuO

2 the process due to which it gets green coating is oxidation reaction