CBSE Class 10 Science 2018 Solved Paper

Question : 16 of 27

Marks: +1, -0

(a) Write the steps involved in the extraction of pure metals in middle of the activity series from carbonate ores.

(b) How is copper extracted from its sulphide ore? Explain the various steps supported by chemical equations. Draw labelled diagram for electrolytic refining of copper.

Solution:

First the carbonate ore of a metal is heated in absence of air. This process is called calcination.

\underset{\underset{\text{Carbon dioxide}}{\text{Zinc carbonate}}}{\mathrm{ZnCO}_3}\xrightarrow[\;\text{ absence of air }\;]{\text{Heaat}}\underset{\text{Zinc oxide}}{\mathrm{ZnO}}+\underset{\text{Carbon dioxide}}{\mathrm{CO}_2}

Then,

\mathrm{ZnO}

is heated with coke.

\mathrm{ZnO} + \underset{\text{Coke}}{\mathrm{C}} \rightarrow \underset{\text{Pure metal}}{\mathrm{Zn}} + \underset{\text{Carbon monoxide}}{\mathrm{CO}}

(b) Copper is extracted from sulphide ore by the process of roasting. It is done in presence of air:

2\mathrm{Cu}_2\mathrm{S} + 3\mathrm{O}_2 \xrightarrow{\;\text{ Heat }\;} \mathrm{Cu}_2\mathrm{O} + 2\mathrm{SO}_2

2\mathrm{Cu}_2\mathrm{O} + \mathrm{Cu}_2\mathrm{S} \xrightarrow{\;\text{ Heat }\;} 6\mathrm{Cu} + 2\mathrm{SO}_2

Electrolytic refining of copper:

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