General Principles And Processes Of Isolation Of Elements

Question
CBSEENCH12010375

(i) Name the method of refining of metals such as Germanium.
(ii)In the extraction of Al, impure Al2O3 is dissolved in conc. NaOH to form sodium aluminate and leaving impurities behind. What is the name of this process?
(iii)What is the role of coke in the extraction of iron from its oxides?

Solution

(i) Zone refining method is the most suitable method for refining metals like germanium (semiconductor).

(ii) In the extraction of aluminium, impure Al2O3 is dissolved in concentrated NaOH to form NaAlO2.
This method is known as leaching of alumina.

Al subscript 2 straight O subscript 3 left parenthesis straight s right parenthesis space plus 2 space NaOH space left parenthesis aq right parenthesis space plus 3 straight H subscript 2 straight O space left parenthesis straight l right parenthesis space rightwards arrow 2 Na left square bracket Al left parenthesis OH right parenthesis subscript 4 right square bracket
(iii) Coke reduces the iron oxide to molten iron metal. Also, coke, when burnt in the blast furnace, supplies the heat required for carrying out the extraction of iron from its oxide.
FeO +C ---> Fe +CO

 

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