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#### model test chapter one

12th Standard EM

Reg.No. :
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Chemistry

Do not involve in any malpractices
Time : 02:00:00 Hrs
Total Marks : 100

Part - A

5 x 1 = 5
1. Bauxite has the composition

(a)

Al2O3

(b)

Al2O3nH2O

(c)

Fe2O3.2H2O

(d)

None of these

2. Roasting of sulphide ore gives the gas (A).(A) is a colourless gas. Aqueous solution of (A) is acidic. The gas (A) is

(a)

CO2

(b)

So3

(c)

SO2

(d)

H2S

3. 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)

4. The metal oxide which cannot be reduced to metal by carbon is

(a)

PbO

(b)

AL2O3

(c)

ZnO

(d)

Feo

5. Which of the metal is extracted by Hall-Heroult process?

(a)

Al

(b)

Ni

(c)

Cu

(d)

Zn

6. Part - B

5 x 2 = 10
7. Assertion :Aluminium is used in the, design of chemical reactors, : medical equipments, , refrigeration units and gas' pipelines.
Reason : Aluminium shows high resistance to corrosion
(a) Both (A) and (R) are true and (R) is the correct explanation of (A)
(b) Both (A) and (R) are true and (R) is not the correct explanation of (A).
(c) (A) true but (R) false
(d) Both (A) and (R) are false.

8. Assertion(A) :Metallic zinc is used in galvanising metals such as iron and steel.
Reason (R) :Zinc is also used to produce die castings
a) Both (A) and (R) are true and (R) is the correct explanation of (A).
b) Both (A) and (R) are true and (R) is not the correct explanation of (A).
c) (A) true but (R) false.
d) Both (A) and (R) are false.

9. Assertion(A) : Zone refining is carried out in an inert gas atmosphere
Reason (R):The metal is treated with a suitable reagent which can form a volatile compound with the metal.
a) Both (A) and (R) are true and (R) is the correct explanation of (A).
b) Both (A) and (R) are true and (R) is not the correct explanation of (A).
c) (A) true but (R) false.
d) Both (A) and (R) are false

10. Assertion :Cuprite is concentrated by froth floatation process.
Reason :Cuprite is the sulphide ore
a) Both assertion and reason are true and the reason is the correct explanation of the assertion.
b) Both assertion and reason are true but the reason is not the correct explanation of the assertion.
|c) Assertion is true, but reason is false.
d) Both assertion and reason are false

11. Assertion :Calamine and Dolomite are the Carbonate ores.
Reason :Calamine is ZnCO3 whereas dolomite is MgCO3.ZnCO3
a) Both assertion and reason are true and the reason is the correct explanation of the assertion.
b) Both assertion and reason are true but the reason is not the correct explanation of the assertion.
c) Assertion is true, but reason is false.
d) Both assertion and reason are false

12. Part - C

5 x 1 = 5
13. I.All ores are minerals
II. All minerals are not ores.
III.Aluminium can be extracted from bauxite.
IV.Aluminium can be extracted from china clay
a) Only I
b) Only II
c) III & IV
d) I, II & III

()

I,II,III

14. I. Copper is the first metal used by the human
II. Aluminuim is used in galvanising metals
III. Aluminium is a good conductor of electricity
IV.Magnets can be made from iron.
a) Only I
b) Only II
c) I, III & IV
d) III & IV

()

I, III & IV

15. I.Ellingham diagram helps to select a suitable reducing agent
II.Magnesite is calcinated to obtain magnesia.
III.Calcination is a process of cooling substances.
IV.Sulphur dioxide is harmful to the environment.
a) I, II & IV
b) Only II
c) Only I
d) III & IV

()

I, II & IV

16. I.Froth flotation is used to concentrate sulphide ores.
II. Magnetic separation is applicable for ferromagnetic ores.
III. Roasting method used to sulphide ores to oxides
IV.Magnetic separation is used to concentrate heavy oxide ores.
a) III & IV
b) Only II
c) Only I
d) I, II & III

()

I, II & III

17. I.Ores are associated with non-metallic impurities
II. Ores are associated with rockymaterials
III. Removal of impurities is known as concentration of ore.
IV. Ellingham diagram shows the stability of different metal oxides.
a) I, II, III & IV b
b) Only II
c) Only I
d) III & IV

()

I, II, III & IV

18. Part - D

5 x 1 = 5
19. Copper pyrite

20. (1)

2CuCO3.Cu(OH)2

21. Malachite

22. (2)

Cu2O

23. Azurite

24. (3)

CuCO3CU(OH)2

25. Cuprite

26. (4)

CuFeS2

27. Calamine

28. (5)

Zn

Part - E

10 x 2 = 20
29. What is the difference between minerals and ores?

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

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

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

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

34. What is metallurgy?

35. Why should we have a ecofriendly metallurgical process?

36. Name some elements that occur as native elements.

37. What is meant by concentration?

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

39. Part - F

5 x 3 = 15
40. Explain zone refining process with an example using the Ellingham diagram given below

41. (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

42. Give the uses of zinc.

43. Explain the electrometallurgy of aluminium

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

45. Part - G

8 x 5 = 40
46. 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.

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

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

49. Give the limitations of Ellingham diagram

50. Explain froth flotation, with diagram.

51. Explain concentration by magnetic separation with diagram.

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

53. Explain refining of nickel by mond's process