(a) Write the balanced chemical equations for the extraction of copper metal from its ore. What is the reducing agent used ? (b) Which reducing agent can be used in the extraction of metals placed at the top of the reactivity series ? Give the name of the process also. (c ) What is the chemical substance formed as green coating when copper reacts with atmospheric gases in moist conditions ?

(a) Write the balanced chemical equations for the extraction of copper

1.	(a) Write the balanced chemical equations for the extraction of copper metal from its ore. What is the reducing agent used ? (b) Which reducing agent can be used in the extraction of metals placed at the top of the reactivity series ? Give the name of the process also. (c ) What is the chemical substance formed as green coating when copper reacts with atmospheric gases in moist conditions ?
Answer» Solution :(a) COPPER is isolated from its SULPHIDE ORE known as copper glance `(Cu_(2)S)` by heating with excess of air or oxygen. `2Cu_(2)S(s) + 3O_(2)(g) overset("heat")rarr 2Cu_(2)O(s) + 2SO_(2)(g)` `2Cu_(2)O(s) + Cu_(2)S(s) overset("heat")rarr6Cu(s) + SO_(2)(g)` Cuprous oxide `(Cu_(2)O)` acts as reducing agent and this process is known as auto-reduction. These metals (K, Na, Mg etc.) can be isolated by carrying out the process of ELECTROLYSIS (electrolytic reduction) from their MOLTEN salts. (c ) The green coating is of basic copper carbonate. It is formed as follows : `2Cu + underset(("Present in air"))ubrace(H_(2)O + CO_(2)+O_(2)) rarrunderset("Basic copper carbonate")(Cu(OH)_(2).CuCO_(3))`