#### 12th Standard Chemistry English Medium Metallurgy Reduced Syllabus Important Questions With Answer Key 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 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. Cupellation is a process used for the refining of

(a)

Silver

(b)

(c)

Copper

(d)

iron

4. Which of the following is commonly used to produce foam in froth floatation process?

(a)

Pine oil

(b)

Cresol

(c)

NaCN

(d)

Xanthate

5. 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)

6. Identify the decreasing order of carbon content in different forms of iron

(a)

Wrought iron> Pig iron> castiron

(b)

Castiron > Pig iron> Wrought iron

(c)

Pig iron> Cast iron> Wrought iron

(d)

Cast iron> Wrought iron> Pig iron

7. Ignition mixture used in aluminothermite process is

(a)

Cr + AI2O3

(b)

Mg + BaO2

(c)

AI + Cr2O3

(d)

Ba+MgO

8. Zinc is extracted from Zinc blende by_________

(a)

Carbon reduction process

(b)

Nitrogen reduction process

(c)

Oxygen reduction process

(d)

All of these

9. Gibb's free energy is given by_______

(a)

$\Delta { G }^{ 0 }=-nF{ E }^{ 0 }$

(b)

$\Delta { G }^{ o }=nF$

(c)

$\Delta { G }^{ o }=nF{ E }^{ o }$

(d)

$\Delta { E }^{ o }=-nF{ G }^{ 0 }$

10. Magnesite is_________

(a)

Magnesium oxide

(b)

Magnesium carbonate

(c)

Magnesium sulphate

(d)

Magnesium chloride

11. The following set of reaction is used for refming titanium. This method is known as___________
${ Ti }_{ (g) }+{ 2I }_{ 2(s) }\longrightarrow { TiI }_{ 4 }\left( vapour \right)$
${ Til }_{ 4 }(va[pour)\longrightarrow Ti_{ (g) }+{ 2I }_{ 2(s) }$

(a)

Hall Herold process

(b)

Mond process

(c)

Van-Arkel process

(d)

Alumino thermic process

12. A mixture containing sulphides of copper and iron is called______

(a)

mineral

(b)

ore

(c)

matte

(d)

matrix

13. The percentage of carbon in high carbon steel is_________

(a)

0.5 - 1%

(b)

0.15 - 1.5%

(c)

0.15 - 1.5%

(d)

0.15 - 0.3%

14. Steelis an alloy of___________

(a)

iron and carbon

(b)

iron and calcium

(c)

copper and carbon

(d)

copper and iron

15. In the thermite proces__________is used as a reducing agent

(a)

AI

(b)

CO

(c)

C

(d)

CO2

16. 2 Marks
10 x 2 = 20
17. What is the role of Limestone in the extraction of Iron from its oxide Fe2O3?

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

19. Describe a method for refining nickel

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

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

22. Name the various refming process

23. Discuss the process of roasting with suitable example.

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

25. 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?

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

27. 3 Marks
10 x 3 = 30
28. Explain zone refining process with an example using the Ellingham diagram given below

29. Give the uses of zinc.

30. Give the basic requirement for vapour phase refining.

31. What is cyanide leaching? Give an example

32. What is vapour phase method?

33. Distinguish Roasting and Calcination

34. What is the role of depressants in froth flotation process?

35. Define the term slag.

36. What is auto-reduction?

37. Write the chemical composition of the following alloys and give anyone of its application.
(i) Bronze
(ii) Brass
(iii) Stainless steelass

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 froth flotation, with diagram.

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

43. List out the application of aluminum

44. List the applications of iron

45. What is zone refining? Describe the principle involved in the purification of the metal by this method.