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Cinnabar (HgS) and galena (PbS) on roast...

Cinnabar (HgS) and galena (PbS) on roasting. often given their respective metals, but zinc blende (ZnS) does not. Explain.

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On roasting all these sulphides are partly converted into their respective oxides. Since the oxides of merćury and lead ane unstable while that of zinc is stable therefore, oxides of mercury and ledd bring about the reduction of their réspective sulphides to the corresponding metats, but .Z nO. does not reduce .Zn S. to .Zn. metal .Hg dotS+2 Hg dotO longrarr Delta rarr 3 Hg+SO_2. tUnszblet .ZnS^h+2 ZnO rarr X.
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V PUBLICATION-GENERAL PRINCIPLES AND PROCESSES OF ISOLATION OF ELEMENTS-QUESTION BANK
  1. a. 'The ore mixed with coke and limestone is introduced into the blast...

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

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

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

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

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

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

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

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  9. Give one important ore of aluminium?

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

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

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

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

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

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

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  16. Which of the following ores can be concentrated by magnetic separation...

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  17. Why is the reduction of a' metal'oxide easier if the metal formed is i...

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  18. What is Ellingham diagram?

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  19. Name the constituents of the following-alloys? (i) Bronze,ii)stainless...

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  20. Name the electrolytic process used for the extraction of aluminium? Wh...

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