Question

A metal ‘X’ acquires a green colour coating on its surface on exposure to air.

Identify the element ‘X’ and name the process responsible for this change.
List two important methods to prevent this process

Answer 1

(i) Metal is copper. The process is corrosion.

(ii) Basic copper carbonate [CUCO3. Cu(OH)2]

The reaction is given as:

2Cu + H2O + CO2 + O2 (present in air) CuCO3.Cu(OH)2.

(iii) • It should be coated with tin

•It should be mixed with other metals to form alloys