#### Chapter one multiple choice creative questions

12th Standard

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Chemistry

Use blue pen only
Time : 00:15:00 Hrs
Total Marks : 20

Part - A

20 x 1 = 20
1. Which metal is used for extraction of Au and Ag and also for galvanisation of iron objects?

(a)

Mg

(b)

Zn

(c)

Cr

(d)

Co

2. Which of the following is not a mineral of aluminium?

(a)

Bauxite

(b)

Cryolite

(c)

China clay

(d)

Malachite

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

(a)

Pine oil

(b)

Cresol

(c)

NaCN

(d)

Xanthate

4. Among the following, one does not belong to calcination, Pick the odd one out.

(a)

${ PBCO }_{ 3 }\overset { \Delta }{ \longrightarrow } PBO+{ CO }_{ 2 }\uparrow$

(b)

${ CaCo }_{ 3 }\overset { \Delta }{ \longrightarrow } Cao+{ CO }_{ 2 }\uparrow$

(c)

$PbS{ O }_{ 3 }\overset { \Delta }{ \rightarrow } PbO+{ 2SO }_{ 2 }\uparrow$

(d)

${ ZnCO }_{ 3 }\overset { \Delta }{ \rightarrow } ZnO+{ CO }_{ 2 }\uparrow$

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 will give respective metal by self reduction?

(a)

Galena (Pbs)

(b)

HgS

(c)

ZnS

(d)

Both (a) & (b)

8. 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)

9. Which among the following reaction represents the formation of slag?

(a)

$Ca{ O }_{ (s) }+{ SiO }_{ 2(s) }\longrightarrow { CaSiO }_{ 3(s) }$

(b)

${ 2C }_{ (s) }+{ O }_{ 2(g) }\longrightarrow { 2CO }_{ (g) }$

(c)

${ Fe }_{ 2 }{ O }_{ 3 }+{ 3CO }_{ (g) }\longrightarrow 2{ Fe }_{ (l) }+{ 3CO }_{ 2(g) }$

(d)

${ CaCO }_{ 3(g) }\longrightarrow { CaO }_{ (s) }+{ CO }_{ 2(g) }$

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

(a)

Phosphorus

(b)

Manganese

(c)

Carbon

(d)

Silicon

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

(a)

Zinc bien de

(b)

Aragonite

(c)

Dolomite

(d)

Carnalite

12. 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

13. Concentration of copper glance is done by

(a)

leaching

(b)

magnetic separation

(c)

froth flotation

(d)

hydraulic washing

14. 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

15. Sodium. magnesium and aluminum can be obtained from their ore by

(a)

electro metallurgy

(b)

pyro metallurgy

(c)

hydro metallurgy

(d)

smelting

16. The blistered appearance of Cu obtained from the reverberatory furance is due to evolution of

(a)

CO2 gas

(b)

S02 gas

(c)

NO2

(d)

Due to evaporation of volatile materials

17. Identify the halide ore among the following

(a)

Epsom Salt

(b)

Pyrolusite

(c)

Anglesite

(d)

Rock Salt

18. Identify the metal that occurs in free state

(a)

Al

(b)

Au

(c)

Mg

(d)

Ca

19. $2PbS+{ 3O }_{ 2 }\longrightarrow 2pbO+{ 2SO }_{ 2 }$ Name the process

(a)

Roasting

(b)

Calcination

(c)

Smelting

(d)

Leaching

20. The process of heating of copper pyrites to remove sulphur is called

(a)

froth flotation

(b)

roasting

(c)

calcination

(d)

smelling