Metallurgy Iit

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METALLURGY IIT-JEE

1) 2) 3)

DISTRIBUTION OF ELEMENTS ON EARTH The most abundant element in the universe is 1) He 2) O 3) C 4) H The core of the earth consists of 1) SiO2 2) Al 3) Fe alloyed with Ni 4) Fe in oxidised form Light rocks in the continental crust contain 1) SiO2 2) Al2O3 + SiO2 3) MgO + SiO2 4) Al2O3 Note : Heavy rocks contain MgO + SiO2

5) 6) 7)

The first four most abundant elements in the earth crust are respectively are 1) O, Si, Al, Fe 2) O, C, H, N 3) O, Si, Al, Ca 4) O, Si, Na, Al The second most abundant element in heavy rocks is 1) Al 2) Mg 3) Fe 4) Si The percentage by weight of oxygen and silicon in the earth crust is 1) 75% 2) 50% 3) 25% 4) 85% Granite is an example of 1) Sedimentary rocks 2) Igneous rocks 3) Heavy rocks 4) None

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4)

Note : Granite is mainly aluminosilicate. It is formed on cooling of magma (  it is an igneous light rock)

8) 9) 10) 11) 12) 13) 14) 15)

The number of elements found in the nature is 1) 100 2) 120 3) 56 4) 88 Sea weeds are an important source of 1) Chlorine 2) Fluorine 3) Bromine 4) Iodine Sea cucumbers are enriched with 1) Iodine 2) Vanadium 3) Bromine 4) None The element present in the enzyme, carbonic anhydrase is 1) Zinc 2) Copper 3) Silver 4) Cadmium The major source of bromine is 1) Horn silver 2) Sea water 3) Galena 4) All The elements which can be recovered on large scale from sea water are 1) Na, Cl, Mg & Br 2) Na, Mg, Al & Li 3) Na, Cl, Fe & C 4) Zn, Cu, Mg & Al The metals which exist in their native state in nature are 1) Cu, Ag, Au & Pt 2) Fe, Zn, Hg & Ni 3) Cu, Ag, Fe & Na 4) Na, Mg, Al & Si O, N and Ar belong to the category 1) Chalcophiles 2) Lithophiles 3) Atmophiles 4) None ORES

1)

2)

The characteristics of an ore is/are 1) high percentage of metal 2) low amounts of easily removable impurities 3) Low expenditure needed for the exraction 4) All Which one of the following is not an oxide ore ? 1) Bauxite 2) Cuprite 3) Magnetite 4) Iron pyrites Note :

3)

Bauxite Al2O3. 2H2O Cuprite Cu2O Magnetite Fe3O 4 Iron pyrites FeS2

Which one of the following is not an ore of iron 1) Magnetite 2) Hematite

3) Siderite

4) Cassiterite

Prepared by V. Aditya vardhan [email protected] Note :

The ore which does not contain Zinc is 1) Zinc blende 2) Zincite Note :

5)

6)

Dolomite : CaCO3. MgCO3 Barytes : BaSO4 Monite : Ca3 (PO4)3. H2O Argentite : Ag2S

3) Cryolite

4) None

Thorite - ThSiO4 Monazite - Phosphate mineral of Thorium and other rare earths Cryolite - Na3AlF6

Galena is the mineral of 1) Zn Note :

4) Cuprite

Malachite - CuCO3 . Cu(OH)2 Azurite - [2 CuCO3]. Cu(OH)2 Copper pyrites - Cu2S. Fe2S3 Cuprite - Cu2O

The silicate mineral of Thorium is 1) Thorite 2) Monazite Note :

9)

4) Argentite

Which among the following is a sulphide ore of copper 1) Malachite 2) Azurite 3) Copper pyrites Note :

8)

4) Zircon

Match the following A) Malachite 1) AgCl B) Horn Silver 2) PbSO4 C) Anglesite 3) Cr2O3. FeO D) Chromite 4) CuCO3.Cu(OH)2 The correct Matching is A B C D 1) 4 1 3 2 2) 4 1 2 3 3) 2 1 4 3 4) 3 1 2 4 The phosphate ore of calcium is 1) Dolomite 2) Barytes 3) Monite Note :

7)

3) Calamine

Zincite - ZnO Zinc blend - ZnS Calamine - ZnCO3 Zircon - ZrSiO4

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4)

Hematite - Fe2O 3 Siderite - FeCO 3 Cassiterite - SnO2

2) Pb

3) Pd

4) Ni

Galena - PbS

10) The element(s) that may occur in the native form in the nature is 1) Gold 2) Silver 3) Copper 4) All 11) The mineral which does not contain fluorine as one of the constituent element is 1) Cryolite 2) Fluorite 3) Both 1 & 2 4) None Note :

Cryolite - Na3AlF6 Fluorite - CaF2

12) Match the following A) Cerussite B) Copper glance C) Limonite D) Epsomite

1) MgSO4. 7H2O 2) 3Fe2O3. 3H2O 3) Cu2S 4) PbCO3

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The correct matching is A B C D 1) 1 2 4 3 2) 4 3 2 1 3) 2 4 3 1 4) 4 3 1 2 13) The chemical composition of wulfenite is 1) CuCO3. Cu(OH)2 2) PbMnO4 3) WO3 4) TiO2 14) The chemical composition of ruby copper is 1) Cu2O 2) Cu2S 3) CuCO3 4) Cu (OH)2 15) The ore of mercury is 1) Cinnabar 2) Fluorspar 3) Phosphorite 4) Argentite Note :

Cinnabar - HgS

Note : Pitch blend - U3O8

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16) The chemical composition of pyrolusite is 1) PbSO4 2) MnO2 3) PbS 17) Pitch blend is the chief ore of 1) Palladium 2) Lead 3) Uranium 18) The silicate ore of zinc is 1) Zinc blend 2) Willemite Note :

Willemite - Zn2SiO4

4) Cesium

3) Mica

19) The chemical composition of chile salt petre is 1) KNO3 2) NaNO3 3) AgNO3 Note :

4) Al2O3

4) Zincite

4) Fe2O3

KNO3 - Indian salt peter NaNO3 - Chile salt peter

20) The composition of spathic iron ore is 1) Fe2S 2) FeS2

3) FeCO3

4) None

Note : Sideritic or spathic iron ore - FeCO3

21) Match the following A) CaMg3 (SiO3)4 1) Pentlandite B) KCl. MgCl2. 6H2O 2) Carnallite C) (Ni, Fe) S 3) Asbestos D) TiO2 4) Rutile The correct matching is A B C D 1) 3 2 1 4 2) 1 2 3 4 3) 3 2 4 1 4) 4 2 1 3 22) The chemical composition of ruby silver is 1) AgCl 2) Ag3SbS3 3) Ag2S 4) AgCO3 23) The sulfide ore of copper which does not contain iron is 1) Copper pyrites 2) Cuprite 3) Chalcocite 4) Cobaltite Note :

Chalcosite - Cu2S Cobaltite - CoAsS

24) Wolframite and Scheelite are the ores of 1) Zinc 2) Manganese 3) Tungsten Note :

4) Gold

Wolframite - (Fe, Mn) WO4 Scheelite - CaWO4

25) The silicate form of beryllium is 1) Beryl 2) Emerald

3) Aquamarine

4) All

Prepared by V. Aditya vardhan [email protected] Note : Beryl is the silicate ore of beryllium (Be3Al2 (SiO3)6) Emerald and Aquamarine are the gemstone varieties of beryl. Emerald - Green colored due to presence of chromium Aquamarine - Transparent variety of beryl with a delicate blue color.

26) The chemical composition of sphalerite is 1) ZnS 2) MnS

3) ZnSO4

4) NaCl

Note : ZnS is also called as Zincblend.

27) Ruby and sapphire are the gemstone varieties of 1) Bauxite 2) Corundum 3) Gibbsite 28) The stone which floats on water is 1) Sand stone 2) Pumice 3) Topaz 29) Cooperite is the ore containing 1) Pt 2) Pd 3) Ni

4) Gold 4) Hyacinth 4) All

Note : Cooperite - (Pt, Pd, Ni) S

30) The mineral containing Lithium is 1) Spodumene 2) Lepidolite

31) The formula of stibnite (antimonite) is 1) SbS2 2) Sb2S 1)

2) 3)

5) 6) 7)

8) 9)

3) Sb2S3

4) Sb2S5

ORE DRESSING Choose the incorrect statement i) The rocky, sandy and siliceous impurities associated with minerals are called gangue ii) Flux is the chemical substance that reacts with infusible gangue by forming a fusible mass called slag. iii) The density of slag is less than that of metal iv) All minerals are ores. The correct statement (s) 1) i & iii 2) i only 3) iv only 4) iii & iv The chemical composition of Thomas slag, used as a fertilizer, is 1) CaSO4. 2H2O 2) Ca3(PO4)2 3) Ca(NO3)2 4) CaSiO3 The basic flux used to remove SiO2 is 1) Al2O3 2) CaO 3) MgCl2 4) None Note : SiO 2 + CaO CaSiO3  Acidic gangue

4)

4) All

Spodumene - LiAl (SiO3)2 - (an inoslilicate) Lepidolite - K Li2Al (Al, Si)3O10(F, OH)2 - (A phyllosilicate) Petalite - LiAlSi4O10 (a tecto silicate)

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Note :

3) Petalite

basic flux

slag

Which of the following ore concentration methods depends upon difference in specific gravity of the ore particles and impurities 1) Levigation method 2) Washing method 3) Wilfley method 4) All The ore which can be concentrated by liquation method is 1) Stibnite 2) Heamatite 3) Magnesite 4) All The ore cassiterite is concentrated by 1) Magnetic method 2) Liquation 3) Froath floatation 4) Wilfley method The separation of magnetite (Fe3O4), Chromite (Cr2O3. FeO) and pyrolusite (MnO2) ores from the non magnetic gangue is usually done by 1) Leaching 2) Magnetic separation 3) Liquation 4) None The magnetic impurity present in cassiterite (SnO)2 is 1) Wolframite 2) Bauxite 3) Galena 4) Willemite The usual technique employed in separation of gangue from hydrophobic sulfide ores is 1) Froth floatation 2) Leaching 3) Roasting 4) Levigation

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10) Choose the correct statement related to froth flotation process a) Collectors like potassium ethyl xanthate are used to enhance the non wettability (hydrophobicity) of mineral particles. b) Pine oil is used as frother, which helps in formation of froth c) Froth is stabilised by adding froth stabilizers like aniline or cresol d) The gangue particles are more hydrophilic than ore particles and sink to the bottom The correct statement (s) 1) a & c 2) a only 3) c & d 4) All H 11) The modifier used to increase the p during froth flotation process is 1) Soda ash 2) Lime 3) H2SO4 4) 1 or 2 12) The depressant used to suppress the floating of galena is 1) Lime 2) Soda ash 3) NaCN 4) All 13) The depressant used to prevent ZnS to form froth is 1) Soda ash 2) NaCN 3) Aniline 4) None

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Note : NaCN forms a layer of Na2[Zn(CN)4] on the surface of ZnS particle and thus by preventing if from the ormation of froth. ZnS + NaCN  Na2[Zn(CN)4] + Na2S This technique is used to separate Galena - PbS (which forms froth selectively) from ZnS particles

14) The separation of ore by converting it into a water soluble compound by reacting with a suitable chemical subtance is called 1) Roasting 2) Leaching 3) Liquation 4) Smelting 15) In the Bayer’s process, the leaching of alumina is done by using 1) Na2CO3 2) NaOH 3) SiO2 4) CaO Note : Alumina is converted to water soluble sodium meta aluminate by treating with sodium hydroxide Al2O3 + 2NaOH  2NaAlO2 + H2O (or) 2 Al2O3 (s) + 2OH- (aq) + 3H2O  2[Al(OH)4]- (aq)

16) The leaching agent used in concentration of argentite ore is 1) NaCN 2) NaCN + O2 3) NaOH Hint :

Ag2S +

4NaCN +

2O2  2Na[Ag(CN)2] + Na2SO4 Soluble complex

17) Cupric oxide can be leached by using 1) NaOH 2) NaCN Hint :

CuO

+

4) O2

H2SO4 

3) H2SO4

CuSO4

+

4) O2

H 2O

water soluble

EXTRACTION OF CRUDE METAL FROM THE ORE 1)

The process of removal of carbon dioxide by heating calamine ore is called 1) Roasting 2) Smelting 3) Calcination 4) All  ZnO  CO2 The ore which is converted to its oxide by calcination process is 1) Cuprite 2) Magnesite 3) Heamatite 4) All The gas evolved during the roasting of sulfide ores is 1) H2S 2) SO3 3) O2 4) SO2 Note : ZnCO3

2) 3)

Example : 4FeS2 + 11O2  2 Fe2O3 + 8SO2 

4)

5)

The reaction which can occur during the roasting of zinc blend at 6500C is 1) 2 ZnS + 3O2  2 ZnO + 2 SO2 2) ZnS + 2O2  ZnSO4 3) Both 1 & 2 4) None During the chloridizing roasting, silver glance is converted to 1) Ag2S 2) AgCl 3) AgNO3 4) Ag

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6)

0

600 C   2 AgCl + Na2SO4 Choose the correct statement

Note :

Ag2S + 2 NaCl + 2O2

a) The free energies of formation ( f G 0 ) of sulphide ores are greater than those of CS2 and

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H2S. Hence the reduction of sulfide ores by carbon and hydrogen is not thermodynamically feasible. b) The heat efficiency of reverberatory furnace is very high. c) The heat efficiency of blast furnace is very low. d) The least temperature in the blast furnace is observed at the top. Correct statement are 1) a only 2) a & d 3) b & c 4) d only 7) The reducing agent used in the reduction of zinc oxide is 1) H2 2) Coke 3) CaCO3 4) Water gas 8) The reducing agent used in the extraction of Nickel from its oxide is 1) Coke 2) Coal gas 3) Water gas 4) Nickel 9) Molydbenum can be extracted from its oxide by reducing with 1) H2 2) Coke 3) O2 4) None 10) The reducing agent used in Goldschmidt alumino thermic process is 1) Al2O3 2) Al 3) AlCl3 4) Fe 11) Chromium can be extracted from its oxide by using aluminium. In this case aluminium acts as 1) Reducing agent 2) Oxidising agent 3) Both 1 & 2 4) None 12) Alumina can be reduced to aluminium by 1) Coke 2) Electrolysis 3) H2 4) CO Note: Aluminium cannot be obtained by chemical reduction due to its strong electro-positive nature and strong affinity with oxygen.

13) The metal obtained during the reduction of cassiterite by coke is 1) Zinc 2) Antimony 3) Tin 4) Carbon 14) The reducing agent which can be used in the reduction of TiCl4 to Ti is 1) Coke 2) Mg 3) H2O 4) CO 15) During smelting process of copper pyrites, most of the iron impurity is removed as 1) Fe2O3 2) FeSiO3 3) FeS 4) FeSO4 Note :

2FeS + 3O2  2 FeO + 2SO2 FeO + SiO2  FeSiO3

16) The composition of matte obtained during smelting of copper pyrites is 1) Cu2O 2) Cu2S 3) Cu2S and little FeS 4) FeS and little Cu2S Note :During the smelting process most of the iron sulfide is removed as FeSiO3 slag. Wheras copper remains mostly in sulfide form (Cu2S).

17) The main reaction that occurs during the roasting of copper pyrites in a reverberatory furnace is 1) Cu2S. Fe2S3 + O2  Cu2S + 2 FeS + SO2 2) Cu2S. Fe2S3 + 6O2  Cu2O + Fe2O3 + 4SO2 3) CuFeS2 + 2O2  CuO + FeO + SO2 4) Cu2S. Fe2S3  Cu2S + Fe2S + 2S 18) Choose the incorrect statement 1) Silica is used as flux to remove iron part from copper pyrites. 2) Blister copper is formed due to auto reduction of Cu2O in the bessemerization process. 3) Pure copper is formed at anode during electrolytic refining of blister copper. 4) Coke is used to produce enough heat to drive the smelting process of copper pyrites. 19) The reducing agent used in Belgian process during the extraction of Zinc is 1) ZnO 2) C 3) CO2 4) ZnS 20) Which of the following reaction represents roasting of sphalerite ore ? 1) 2Cu2S + 3O2  2Cu2O + 2SO2  2) ZnS + O2  ZnO + SO2 

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22)

23)

24)

25) 26) 27) 28) 29) 30) 31) 32)

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21)

3) ZnO + C  Zu + CO  4) Ag2S + NaCN + O2  Na[Ag(CN)2] The charge feed into the blast furnace during the extraction of cast iron is 1) 8:4:1 parts by weight of roasted ore, coke and silica 2) 8:4:1 parts by weight of roasted ore, coke and lime stone 3) 8:4:1 parts by weight of roasted ore, silica and lime stone 4) 8:4 parts by weight of roasted ore and lime stone The reaction that occurs in the zone of heat absorption in the blast furnace during the extraction of cast iron is 1) Fe2O3 + 3C  2Fe + 3CO 2) Fe2O3 + 3CO  2Fe + 3CO2 3) CaO + SiO2  CaSiO3 4) both 1 and 2 The reaction that does not occur in the zone of reduction in the blast furnace during the extraction of cast iron is 1) Fe2O3 + 3C  2Fe + 3CO 2) Fe2O3 + 3CO  2Fe + 3CO2 3) CaCO3  CaO + CO2 4) both 1 and 2 The endothermic reaction that occurs in the zone of heat absorption in the blast furnace during the extraction of cast iron is 1) CO2 + C  2CO 2) CaCO3  CaO + CO2 3) C + O2  CO2 4) both 1 and 2 Silica present as impurity in iron ore is removed as slag by reacting with 1) CaO 2) C 3) CO 4) all The temperature of zone of fusion in the blast furnace is in the range of 1) 8000C - 10000C 2) 4000C - 7000C 3) 12000C - 13000C 4) 13000C - 15000C Combustion of coke and melting of iron occurs in the following region of blast furnace 1) Zone of reduction 2) Zone of heat absorption 3) Zone of fusion 4) None The percentage of carbon in cast iron is 1) 4% 2) 0.2% 3) 2% 4) 0.4% The percentage of carbon in wrought iron is 1) 4% 2) 0.2% 3) 2% 4) 0.4% The Puddler’s candles are produced due to burning of 1) carbon 2) carbon monoxide 3) hydrogen 4) None The alloy of iron containing 15-20% Mn and 60% C is called 1) Steel 2) spiegeleisen 3) Pig iron 4) Stainless steel Choose the incorrect statement related to the manufacture of steel. 1) The composition of steel can not be controlled during the bessemer converter process. 2) Iron ore, scrap iron and low grade pig iron can be used during bessemer converter process. 3) The composition of steel can be controlled during the open hearth process. 4) There is loss of iron during bessemer converter process due to the use of blast of air.

REFINING OF METALS 1) 2)

3) 4) 5)

Impure tin can be refined by 1) Roasting 2) Liquation 3) Smelting 4) Calcination The method which uses green wood poles to reduce the oxide impurites from impure metals is called 1) Cupellation 2) Green wood process 3) Poling 4) Smelting The metal which can be refined by distillation process is 1) Zn 2) Cd 3) Hg 4) All The best method used to refine gold metal is 1) Distillation 2) Electrolysis 3) Bassemerization 4) Oxidation The suitable method used to remove lead impurity from impure silver is 1) Poling 2) Cupellation 3) Distillation 4) All

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6) 7)

Highly pure silicon can be obtained by 1) Electrolysis 2) Roasting 3) Zone refining 4) Liquation The complex of nickel formed during Mond’s process is 1) NiCl4 2) Ni(CO)4 3) Ni(CO)6 4) K2[Ni (CN)4] Note : Mond’s process is a vapour phase refining method of nickel. In this process, nickel is converted to volatile nickel tetracarbonyl by heating in a stream of carbon monoxide at 330-350K. Then the complex is subjected to dissociation by heating at higher temperature (450 - 470K) to get pure nickel Ni

+ 4 CO

330-350K 

impure

8)

Ni (CO) 4

450-470K 

Volatile

Ni + 4CO Pure

The vapour phase method used to purify zirconium is 1) Van Arkel method 2) Mond’s process 3) Gibb’s method

4) Bayer’s process

Zr impure

+ 2I 2

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Note : In the van Arkel method, Zirconium is heated in iodine vapour at about 870K to form volatile ZrI4. The latter when heated over a tungsten filament at 2075K gives pure Zirconium. 870 K 

Zr I 4

2070K   

(Volatile)

Zr + 2 I 2 Pure

Titanium can also be refined by this method.

Note: Key to the questions and updates, if any, can be downloaded from http://groups.google.com/group/adichemadi