#### 12th Standard Chemistry English Medium Metallurgy Reduced Syllabus Important Questions 2021

12th Standard

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Chemistry

Time : 01:00:00 Hrs
Total Marks : 100
Multiple Choice Questions
15 x 1 = 15
1. Match items in column - I with the items of column – II and assign the correct code.

 Column-I Column-II A. Cyanide process (i) Ultrapure Ge B Froth floatation process (ii) Dressing of ZnS C Electrolytic reduction (iii) Extraction of Al D Zone refining (iv) Extraction of Au (v) Purification of Ni
(a)
 A B C D iv ii iii i
(b)
 A B C D (i) (ii) (iii) (iv)
(c)
 A B C D (iii) (iv) (v) (i)
(d)
 A B C D (ii) (iii) (i) (v)
2. Which one of the following ores is best concentrated by froth – floatation method?

(a)

Magnetite

(b)

Hematite

(c)

Galena

(d)

Cassiterite

3. Considering Ellingham diagram, which of the following metals can be used to reduce alumina? (NEET-2018)

(a)

Fe

(b)

Cu

(c)

Mg

(d)

Zn

4. The following set of reactions are used in refining Zirconium
$(impure)+2I_{ 2 }\overset { 523k }{ \longrightarrow } ZrI_{ 4 }$
${ ZrI }_{ 4 }\overset { 1800K }{ \longrightarrow } Zr(pure)+{ 2I }_{ 2 }$
This method is known as

(a)

Liquation

(b)

van Arkel process

(c)

Zone refining

(d)

Mond’s process

5. Which of the following is incorrect with respect to metallurgy of iron in the blast furnace?

(a)

Zone of combustion : $C+{ O }_{ 2 }\rightarrow { CO }_{ 2 }$

(b)

Zone of heat absorption : ${ CO }_{ 2 }\rightarrow C+{ O }_{ 2 }$

(c)

Zone of slag formation : $CaO+{ SiO }_{ 2 }\rightarrow CaSiO_{ 3 }$

(d)

Zone of reduction : ${ Fe }_{ 2 }{ O }_{ 3 }3C\rightarrow 3CO+2Fe$

6. Name the process by which elements such as germanium, silicon and galium are refined.

(a)

Vapour phase method

(b)

Electrolytic refining

(c)

Zone refining

(d)

Van-Arkel method

7. Which of the following mineral contains calcium as well as magnesium?

(a)

Zinc bien de

(b)

Aragonite

(c)

Dolomite

(d)

Carnalite

8. Identify the halide ore among the following

(a)

Epsom Salt

(b)

Pyrolusite

(c)

Anglesite

(d)

Rock Salt

9. Zinc blende is_________

(a)

ZnS

(b)

PbS

(c)

Ag2S

(d)

Cu2S

10. Magnetic separation it is based on the difference in the_________ of the ore and the impurities.

(a)

magnetic properties

(b)

chemical properties

(c)

physical properties

(d)

melting point

11. Na[Ag(CN)2] is _________.

(a)

Sodium aurocyanide

(b)

Sodium meta aluminate

(c)

Aluminosilicate

(d)

Sodium dicyano argentate

12. Semiconductors are purified by_______method.

(a)

Zone refining

(b)

Electrolytic refining

(c)

Mond's process

(d)

Beisemerisation

13. Froth floatation process is suitable for concentrating ______ores.

(a)

oxide

(b)

carbonate

(c)

sulphide

(d)

halide

14. Metal oxide is converted into metal by the:_______ process.

(a)

Calcination

(b)

roasting

(c)

smelting

(d)

beesemerisation

15. Galena is_________

(a)

PbS

(b)

ZnS

(c)

Ag2S

(d)

FeS2

16. 2 Marks
10 x 2 = 20
17. What are the difference between minerals and ores?

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

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

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

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

22. What is leaching?

23. What is distillation?

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

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

26. Define roasting,

27. 3 Marks
10 x 3 = 30
28. Using the Ellingham diagram,
(A) Predict the conditions under which
(i) Aluminium might be expected to reduce magnesia.
(ii) Magnesium could reduce alumina.
(B) it is possible to reduce Fe2O3 by coke at a temperature around 1200K

29. What is meant by ammonia leaching?

30. Explain alkali leaching in the extraction of aluminum,

31. How is acid leaching done for the sulphide ores?

32. Distinguish Roasting and Calcination

33. Write the molecular composition of the following ores and mentions it metal : magnetite) calamine and bauxite.

34. (i) Which of the following metals cannot: be extracted by the smelting process : 1 AI, Zn, Fe and Pb. Give reasons.
(ii) Which one is a good reducing agent (C or CO) for Fe2O3, below 1073 k?

35. What is auto-reduction?

36. What is liquation?

37. Copper and silver lie low in the electrochemical series and yet they are found in the combined state as sulphides in nature. Comment.

38. 5 Marks
7 x 5 = 35
39. Describe the role of the following in the process mentioned.
(i) Silica in the extraction of copper.
(ii) Cryolite in the extraction of aluminium.
(iii) Iodine in the refining of Zirconium.
(iv) Sodium cyanide in froth floatation.

40. Explain the principle of electrolytic refining with an example.

41. Explain concentration by magnetic separation with diagram.

42. In the extraction of copper, explain the smelting process.

43. Explain refming of titanium by Van-Arkel method.

44. How can you separate alumina from silica in a bauxite ore

45. Write short note on the following:
(i) The process in which no external reducing agent is used.
(ii) The process which is used for highly electro positive metal.
(iii) Write the equation involved in the thermite process.