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In a classroom discussion Raju said that...

In a classroom discussion Raju said that silver ores and native gold have to be leached with metal cyanides.Is this statement true?Justify you answer?

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Raju.s statement is correct. For example, when silver ore is treated with NaCN forming a complex. The solution is further treated with Zn which displaces.Ag from the complex. .Ag_2 ~S+4 NaCN rarr 2 Na[Ag(CN)_i]+Na_2 ~S. 2Na[ ..Ag(CN)_2]+Zn rarr Na_2[Zn(CN)_4]+2 ~A_2 ~g. Similarly, native gold is treated with KCN solution and it is recovered from the solution by adding Zn. .4 Au+8 KCN+O_2+2 H_2 O mapsto 4 ~K[Au(CN)_2]+4 KOH. .2 ~K[Au cdot(CN)_2]+Zn rarr K_1[dotZ n(CN)_1]+2 Au.
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V PUBLICATION-GENERAL PRINCIPLES AND PROCESSES OF ISOLATION OF ELEMENTS-QUESTION BANK
  1. Given below is a symbolic parktng zone. Select stitable term from thos...

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  2. In a classroom discussion Ramu said that ocean is a store house of ele...

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  3. In a classroom discussion Raju said that silver ores and native gold h...

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  4. Froth floatation process is convenient for the concentration of sulphi...

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  5. A.Name the metallurgical refining technique used for purification of N...

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  6. a. 'The ore mixed with coke and limestone is introduced into the blast...

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  7. How does NaCN act as a depressant in preventing ZnS from forming the ...

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  8. Cinnabar (HgS) and galena (PbS) on roasting. often given their respect...

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  9. Although thermodynamically feasible,in practice, magnesium metal is no...

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  10. In general which metals do you expect.to occur in the native state in ...

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  11. Why is it advantageous to roast a sulphide ore before reduction?

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  12. A, white powder (A) whén heated gave off a coloúrless gas (B) which tu...

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  13. Describe the priniciple of extraction of each of the following i)Sn fr...

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  14. Give one important ore of aluminium?

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  15. Name the four, most abundant elements in the earth's crust? Arrange.th...

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  16. Copper and silver lie below in the electrochemical series and yet they...

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  17. Name,the method used for refining of (i) Nićkel (ii) Zireonium

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  18. A sample of galena (PbS) is contaminated with zinc blende (ZnS). Name ...

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  19. Metal sulphides occur mainly in rocksand metal halides in lakes and se...

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  20. Prudict the mode of occurrence of the following metals. (i) Highly rea...

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