Question

Explain how the following metals are obtained from their compounds by reduction process :
(a) Metal X which is low in reactivity series.
(b) Metal 1' which is in the middle of reactivity series.
(c) Metal Z which is high in the reactivity series.


CBSE Class X Science SA 2 (3 Marks)

Answer 1

Answer:

c) metal 1'whichis in the middle of reactivity series

Answer 2

a)Metal X is reduced directly by heating the metal ores

b)Metal Y which is in the middle of the reactivity series is extracted by heating metal ores to get oxides and sulphides are reduced by electrolysis or heating with carbon.(calcination, roasting)

c)Metal Z which is highly reactive is reduced by using electrolytic reduction technique of the molten compounds.

Explanation:

• metals which have low reactivity like mercury Hg, gold Au, silver Ag etc do not react with air easily. therefore generally they are roasted from the chosen ore to obtain impure metals
• Metals which have intermediate reactivity like Pb, Zn etc have their ores of the composition carbonates, bicarbonates etc. They decompose to oxides, sulphides on heating in presence or absense of air(usually called calcination, roasting). Then carbon is used to reduce these metals from obtained oxides, sulphides at particular temperatures. They are mixed with carbon and heated in absence of air.
• Metals which are highly reactive like lithium, potassium are obtained by electrolytic reduction of their compounds in molten state like NaCl, KCl etc.