" /> -->

#### Metallurgy one marks two marks three marks five marks part2

12th Standard EM

Reg.No. :
•
•
•
•
•
•

Chemistry

Answer all the following question:
Time : 02:00:00 Hrs
Total Marks : 100
Part-A
20 x 1 = 20
1. Which one of the following reaction represents calcinations?

(a)

$2Zn+{ O }_{ 2 }\rightarrow 2ZnO$

(b)

$2ZnS+3O_{ 2 }\rightarrow 2ZnS+3O_{ 2 }\rightarrow 2ZnO_{ 2 }\rightarrow 2ZnO+2SO_{ 2 }$

(c)

$MgCO_{ 3 }\rightarrow MgO+CO_{ 2 }$

(d)

Both (a) and (c)

2. Which one of the following is not feasible

(a)

$Zn(s)+C{ u }^{ 2+ }\left( aq \right) \rightarrow Cu\left( s \right) +{ Zn }^{ 2+ }(aq)$

(b)

$Cu(s)+Z{ n }^{ 2+ }(aq)\longrightarrow Zn(s)+{ Cu }^{ 2+ }(aq)$

(c)

$Cu(s)+2Ag^{ + }(aq)\longrightarrow Ag(s)+{ Cu }^{ 2+ }(aq)$

(d)

$Fe(s)+{ Cu }^{ 2+ }(aq)\longrightarrow Cu(s)+{ Fe }^{ 2+ }(aq)$

3. Extraction of gold and silver involves leaching with cyanide ion. silver is later recovered by (NEET-2017)

(a)

Distillation

(b)

Zone refining

(c)

Displacement with zinc

(d)

liquation

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

(a)

Fe

(b)

Cu

(c)

Mg

(d)

Zn

5. Which of the following is used for concentrating ore in metallurgy?

(a)

Leaching

(b)

Roasting

(c)

Froth floatation

(d)

Both (a) and (c)

6. The incorrect statement among the following is

(a)

Nickel is refined by Mond’s process

(b)

Titanium is refined by Van Arkel’s process

(c)

Zinc blende is concentrated by froth floatation

(d)

In the metallurgy of gold, the metal is leached with dilute sodium chloride solution

7. In the electrolytic refining of copper, which one of the following is used as anode?

(a)

Pure copper

(b)

Impure copper

(c)

Carbon rod

(d)

Platinum electrode

8. Which of the following plot gives Ellingham diagram

(a)

$\Delta SVsT$

(b)

$\Delta { G }^{ 0 }VsT$

(c)

$\Delta { G }^{ 0 }Vs\cfrac { 1 }{ T }$

(d)

$\Delta { G }^{ 0 }Vs{ T }^{ 2 }$

9. In the Ellingham diagram, for the formation of carbon monoxide

(a)

$\left( \cfrac { \Delta { S }^{ 0 } }{ \Delta T } \right)$

(b)

$\left( \cfrac { \Delta { G }^{ 0 } }{ \Delta T } \right)$ is positive

(c)

$\left( \cfrac { \Delta { G }^{ 0 } }{ \Delta T } \right)$ is negative

(d)

initially $\left( \cfrac { \Delta T }{ \Delta { G }^{ 0 } } \right)$ is positive, after 700oC,$\left( \cfrac { \Delta { G }^{ 0 } }{ \Delta T } \right)$ is negative

10. Which of the following is not true with respect to Ellingham diagram?

(a)

Free energy changes follow a straight line. Deviation occurs when there is a phase change.

(b)

The graph for the formation of CO2 is a straight line almost parallel to free energy axis.

(c)

Negative slope of CO shows that it becomes more stable with increase in temperature

(d)

Positive slope of metal oxides shows that their stabilities decrease with increase in temperature

11. 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

12. In the extraction of copper from its sulphide ore, the metal is finally obtained by the reduction of cuprous oxide with

(a)

Iron sulphide (FeS)

(b)

Carbon monoxide (CO)

(c)

Copper (I) sulphide (Cu2S)

(d)

Sulphur dioxide (S02)

13. Which one of the following element is present as a~ impurity in pig iron?

(a)

Phosphorus

(b)

Manganese

(c)

Carbon

(d)

Silicon

14. In the froth-floatation process the collectors such as pine oil and xanthates, etc enhance.

(a)

Non-wettability of the mineral particles in froth.

(b)

Non-wettability of the mineral particles in water

(c)

Non-wettability of the gangue particles in froth

(d)

Non-wettability of the gangue particles in water

15. Malachite has______ composition.

(a)

2CuCO3.Cu(OH)2

(b)

2CuCO3.Cu(OH)2

(c)

Cu2O

(d)

Cu2S

16. Zinc blende is_________

(a)

ZnS

(b)

PbS

(c)

Ag2S

(d)

Cu2S

17. Sulphide ore is converted to oxide form by using the process_________

(a)

Calcination

(b)

Roasting

(c)

Smelting

(d)

Leavhing

18. ${ Zn }_{ (s) }+2\left[ Au(CN)_{ 2 } \right] ^{ - }_{ (aq) }\longrightarrow \left[ Zn(CN)_{ 4 } \right] ^{ 2- }_{ (aq) }+2Au{ { u }_{ (s) } }$ In the above equation) the oxidation state of metallic;gold is_______

(a)

1

(b)

0

(c)

+2

(d)

-2

19. Froth floatation process is suitable for concentrating ______ores.

(a)

oxide

(b)

carbonate

(c)

sulphide

(d)

halide

20. Steelis an alloy of___________

(a)

iron and carbon

(b)

iron and calcium

(c)

copper and carbon

(d)

copper and iron

21. Part-B
10 x 2 = 20
22. What is the difference between minerals and ores?

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

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

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

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

27. Describe a method for refining nickel

28. What is metallurgy?

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

30. Write the two similarities between calcination and roasting.

31. List out the commercial uses of iron.

32. Part-C
10 x 3 = 30
33. Explain zone refining process with an example using the Ellingham diagram given below

34. (A) Predict the conditions under which
(i) Aluminium might be expected to reduce magnesia.
(ii) Magnesium could reduce alumina.
(B) Carbon monoxide is more effective reducing agent than carbon below 983K but, above this temperature, the reverse is true –Explain.
(c) it is possible to reduce Fe2O3 by coke at a temperature around 1200K

35. Give the uses of zinc.

36. Explain the electrometallurgy of aluminium

37. Explain the following terms with suitable examples.
(i) Gangue
(ii) slag

38. Give the basic requirement for vapour phase refining.

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

40. Explain roasting with an example.

41. (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?

42. What is liquation?

43. Part-D
6 x 5 = 30
44. 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.

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

46. The selection of reducing agent depends on the thermodynamic factor: Explain with an example.

47. Write a short note on electrochemical principles of metallurgy.

48. Explain froth flotation, with diagram.

49. List the applications of iron