Q18 of 26 Page 70

Name the substance formed on the surface of copper when it reacts slowly with moist CO2 in the air.

When copper reacts with the moist CO2 present in the air, it will loose its shiny brown surface and green coating will be formed on the surface of the copper. This green coating is of CuCO3 and Cu(OH)2. The reaction is:


2Cu + CO2 + H2O + O2→ CuCO3 and Cu(OH)2.


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With the help of a labelled diagram, explain the process of electrolytic refining of copper.

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