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#### Metallurgy two marks

12th Standard EM

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Chemistry

answer the following question:
Time : 02:00:00 Hrs
Total Marks : 70
Part-A
35 x 2 = 70
1. What is the difference between minerals and ores?

2. What are the various steps involved in extraction of pure metals from their ores?

3. What is the role of Limestone in the extraction of Iron from its oxide Fe2O3?

4. Which type of ores can be concentrated by froth floatation method? Give two examples for such ores.

5. Out of coke and CO, which is better reducing agent for the reduction of ZnO? Why?

6. Describe a method for refining nickel

7. What is metallurgy?

8. Why should we have a ecofriendly metallurgical process?

9. Name some elements that occur as native elements.

10. What is meant by concentration?

11. Can the same method of extraction be used for all metals

12. Name some common methods of ore concentration.

13. Name the two steps involved in the extraction of crude metal

14. Name some reducing agents used to convert Metal oxides to metal

15. Name the metals that are obtained from their oxides using hydrogen as reducing agent.

16. Name the various refming process

17. Discuss the use of an acidic flux in metallurgy.

18. Why are sulphide ores converted to oxide form before reduction to metal?

19. Discuss the process of roasting with suitable example.

20. Write the two similarities between calcination and roasting.

21. Name the ore that can be concentrated by magnetic separation method.

22. Why is the froth floatation method selected for the concentration of sulphide ores?

23. What is Ellingham diagram? or
What does Ellingham diagram represent?

24. Name some depressing agents

25. What is the role of silica in the extraction of copped? (or)
Describe the role of SiO2 in the extraction of Cu from Copper matte.

26. The reaction
${ Cr }_{ 2 }{ O }_{ 3 }+2{ Al }_{ (s) }\longrightarrow { Al }_{ 2 }O_{ 3 }+2Cr$
$\Delta { G }^{ 0 }=-421KJ$ is thermodynamically feasible why does it not take place at room temperature?

27. What is the role of graphite rods in the electro metallurgy of aluminium?

28. Write the chemical reactions involved in the extraction of gold by cyanide process. Also give the role of zinc in the extraction.

29. Name and discuss the principle involved in obtaining silicon of high purity.

30. List out the commercial uses of iron.

31. Give reason : Extraction of copper directly from sulphide ores is less favourable than from its oxide ores through reduction.

32. What are the different methods of concentration of ores?

33. Define metallurgy.

34. What is calcination? Give example.

35. Define roasting,