Previous year Questions (2016-20) - General Principles and Processes of Isolation of Elements Notes | EduRev

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Q.1. The purest form of commercial iron is    (2020)
(1) Pig iron
(2) Wrought iron
(3) Cast iron
(4) Scrap iron and pig iron
Ans. (2) 

The purest form of the commercial iron is wrought iron.

Q.2. The refining method used when the metal and the impurities have low and high melting temperatures, respectively, is    (2020)
(1) Liquation
(2) Vapor phase refining
(3) Zone refining
(4) Distillation

Ans. (1) 

Liquation refining is used to separate a low melting metal like, tin from the high melting impurities.

Q.3. Among the reactions (I) – (IV), the reaction(s) that does/do not occur in the blast furnace during the extraction of iron is/are    (2020)
(I) CaO + SiO2 → CaSiO3
(II) 3Fe2O3 + CO → 2Fe3O4 + CO2
(III) FeO + SiO2 → FeSiO3
(IV) Previous year Questions (2016-20) - General Principles and Processes of Isolation of Elements Notes | EduRev
(1) (I)
(2) (I) and (IV)
(3) (III) and (IV)
(4) (IV)
Ans. (3) 

The feasible reactions occur in blast furnace is:

Q.4. According to the following diagram, A reduces BO2 when the temperature is

Previous year Questions (2016-20) - General Principles and Processes of Isolation of Elements Notes | EduRev    (2020)
(1) < 1400°C
(2) > 1400°C
(3) > 1200°C but < 1400°C
(4) < 1200°C
Ans. (2) 

From the given graph, the line of A intersects B at temperature greater than 1400°C, thus, A can reduce BO2 at temperature greater than 1400°C.

Q.5. The ore that contains both iron and copper is:    (2019)
(1) copper pyrites
(2) malachite
(3) dolomite
(4) azurite
Ans.
(1)
Amongst the given ores, copper pyrite (CuFeS2), dolomite (MgCO3.CaCO3), malachite [CuCO3.Cu(OH)2], azurite [2CuCO3.Cu (OH)2], copper pyrite contains both copper and iron.

Q.6. The correct statement regarding the given Ellingham diagram is:    (2019)
Previous year Questions (2016-20) - General Principles and Processes of Isolation of Elements Notes | EduRev
(1) At 1400°C, Al can be used for the extraction of Zn from ZnO
(2) At 500°C, coke can be used for the extraction of Zn from ZnO
(3) Coke cannot be used for the extraction of Cu from Cu2O.
(4) At 800°C, Cu can be used for the extraction of Zn from ZnO
Ans.
(1)
In the given Ellingham diagram, the metal which has a lower value of ΔG° (more negative) can reduce a metal oxide whose curve lies above it. So, Al can reduce ZnO at 1400 °C.

Q.7. Hall-Heroult’s process is given by:    (2019)
(1) Cu2+ (aq) + H2(g) → Cu(s) + 2H+ (aq)
(2) Cr2O3 + 2AI → Al2O3 + 2Cr
(3) 2Al2O3 + 3C → 4Al + 3CO2
(4) ZnO + C Previous year Questions (2016-20) - General Principles and Processes of Isolation of Elements Notes | EduRev Zn + CO
Ans.
(3)
Hall Heroult’s process is an electrochemical process used in extraction of Al from alumina.

Q.8. Match the ores (column A) with the metals (column B):    (2019)
Previous year Questions (2016-20) - General Principles and Processes of Isolation of Elements Notes | EduRev
(1) (I) - (a); (II) - (b); (III) - (c); (IV) - (d)
(2) (I) - (c); (II) - (d); (III) - (b); (IV) - (a)
(3) (I)-(c); (II)-(d); (III)-(a); (IV)-(b)
(4) (I)-(b); (II)-(c); (III)-(d); (IV)-(a)
Ans.
(2)
Siderite = FeCO3 
Calamine = ZnCO3 
Malachite = CuCO3.Cu(OH)2 
Kaolinite = Al2Si2O5(OH)4

Q.9. The reaction that does NOT define calcination is:    (2019)
(1) Previous year Questions (2016-20) - General Principles and Processes of Isolation of Elements Notes | EduRev
(2) Previous year Questions (2016-20) - General Principles and Processes of Isolation of Elements Notes | EduRev
(3) Previous year Questions (2016-20) - General Principles and Processes of Isolation of Elements Notes | EduRev
(4) Previous year Questions (2016-20) - General Principles and Processes of Isolation of Elements Notes | EduRev
Ans.
(2)
Calcination involves heating of carbonates or hydrated oxides in absence of air.
Previous year Questions (2016-20) - General Principles and Processes of Isolation of Elements Notes | EduRev is roasting (heating in a regular supply of air).

Q.10. Match the following items in column I with the corresponding items in column II.    (2019)
Previous year Questions (2016-20) - General Principles and Processes of Isolation of Elements Notes | EduRev
(1) (i) → (B); (ii) → (C); (iii) → (A); (iv) → (D)
(2) (i) → (C); (ii) → (B); (iii) → (D); (iv) → (A)
(3) (i) → (D); (ii) → (A); (iii) → (B); (iv) → (C)
(4) (i) → (C); (ii) → (D); (iii) → (B); (iv) → (A)
Ans.
(4)
(i) Na2CO3.10H2O → Solvay process
(ii) Mg(HCO3)2 → Temporary hardness
(iii) NaOH → Castner-Kellner process
(iv) Ca3Al9O6 → Portland cement

Q.11. In the Hall-Heroult process, aluminium is formed at the cathode. The cathode is made out of:    (2019)
(1) Pure aluminium
(2) Carbon
(3) Copper
(4) Platinum
Ans.
(2)
In Hall-Heroult process, steel vessel with lining of carbon acts as cathode and graphite is used as anode.

Q.12. The pair that does NOT require calcination is:    (2019)
(1) ZnO and MgO
(2) ZnO and Fe2O3.xH2O
(3) ZnCO3 and CaO
(4) Fe2Oand CaCO3.MgCO3
Ans.
(1)
Calcination involves the conversion of metal carbonates or hydrated oxides into metal oxides. ZnO and MgO are oxides, therefore, does not require calcination.

Q.13. With respect to an ore, Ellingham diagram helps to predict the feasibility of its    (2019)
(1) Electrolysis 
(2) Zone refining
(3) Vapour phase refining
(4) Thermal reduction
Ans. 
(4)
Ellingham diagram is a graph showing the temperature dependence of the stability for compounds. It is used to select reducing agent so it helps to predict feasibility of its thermal reduction.

Q.14. The Mond process is used for the:    (2019)
(1) purification of Ni
(2) extraction of Mo
(3) purification of Zr and Ti
(4) extraction of Zn
Ans.
(1)
Mond’s process is used for purification of Ni
Previous year Questions (2016-20) - General Principles and Processes of Isolation of Elements Notes | EduRev

Q.15. The ore that contains the metal in the form of fluoride is:    (2019)
(1) cryolite
(2) malachite
(3) magnetite
(4) sphalerite
Ans.
(1)
Previous year Questions (2016-20) - General Principles and Processes of Isolation of Elements Notes | EduRev

Q.16. Assertion: For the extraction of iron, haematite ore is used.
Reason: Haematite is a carbonate ore of iron.    (2019)
(1) Only the reason is correct
(2) Both the assertion and reason are correct, but the reason is not the correct explanation for the assertion.
(3) Both the assertion and reason are correct and the reason is the correct explanation for the assertion.
(4) Only the assertion is correct.
Ans.
(4)
For the extraction of iron, haematite ore (Fe2O3) is used

Q.17. The one that is not a carbonate ore is:    (2019)
(1) malachite
(2) calamine
(3) siderite
(4) bauxite
Ans.
(4)
Previous year Questions (2016-20) - General Principles and Processes of Isolation of Elements Notes | EduRev

Q.18. Match the refining methods (Column I) with metals (Column II).    (2019)
Previous year Questions (2016-20) - General Principles and Processes of Isolation of Elements Notes | EduRev
(1) (I) - (c); (II) - (a); (III) - (b); (IV) - (d)
(2) (I) - (b); (II) - (c); (III) - (d); (IV) - (a)
(3) (I)-(c); (II)-(d); (III)-(b); (IV)-(a)
(4) (I)-(b); (II)-(d); (III)-(a); (IV)-(c)
Ans.
(3)
Liquation is used for Sn, zone refining is used for Ga, Mond's process is used for refining of Ni and van Arkel method is used for Zr,
So, correct match is
(I)-(c); (II)-(d); (III)-(b); (IV)-(a)

Q.19. The alloy used in the construction of air crafts is:    (2019)
(1) Mg - Al
(2) Mg - Zn
(3) Mg - Sn
(4) Mg - Mn
Ans.
(1)
In manufacturing of aircraft an alloy of Mg and Al called magnalium is used due to its light weight and high strength.

Q.20. The correct statement is:    (2019)
(1) aniline is a froth stabilizer.
(2) zincite is a carbonate ore.
(3) sodium cyanide cannot be used in the metallurgy of silver.
(4) zone refining process is used for the refining of titanium.
Ans.
(1)
Ti is refined by van Arkel method. Silver is leached by dilute solution of NaCN. Zincite is oxide ore of zinc i.e. ZnO. Aniline is a froth stabilizer.

Q.21. The idea of froth floatation method came from a person X and this method is related to the process Y of ores, X and Y, respectively, are:    (2019)
(1) fisher woman and concentration
(2) washer woman and concentration
(3) fisher man and reduction
(4) washer man and reduction
Ans.
(2)
Froth floatation was discovered by washer woman. It is a method of concentration of ores.

Q.22. The correct statement is:    (2019)
(1) leaching of bauxite using concentrated NaOH solution gives sodium aluminate and sodium silicate.
(2) the Hall-Heroult process is used for the production of aluminium and iron.
(3) pig iron is obtained from cast iron.
(4) the blistered appearance of copper during the metallurgical process is due to the evolution of CO2.
Ans.
(1)
During metallurgy of aluminium, when bauxite (powdered ore) is treated with NaOH (cone), sodium aluminate (Na[Al(OH)4]) is formed and impurity (SiO2) present in bauxite dissolves by forming sodium silicate (Na2SiO3)
Al2O3(s) + 2NaOH(aq) + 3H3O(l) → 2Na [Al (OH)4] (aq)
Cast iron is obtained from pig iron.
Blister of copper is due to evolution of SO2.
Hall Heroult process is used for the production of aluminium.

Q.23. In the extraction of copper from its sulphide ore, metal is finally obtained by the oxidation of cuprous sulphide with:    (2018)
(1) SO2
(2) Fe2O3
(3) Cu2O
(4) CO
Ans.
(3)
Cu2S + 2Cu2O → 6Cu + SO2
It is an example of auto-reduction, CuO2 is reduced to copper metal.

Q.24. Which one of the following ores is best concentrated by froth floatation method?    (2016)
(1) Magnetite
(2) Siderite
(3) Galena
(4) Malachite
Ans.
(3)
PbS, i.e. Galena is best concentrated by froth floatation method.

Q.25. The plot shows the variation of ln Kp versus temperature for the two reactions.
Previous year Questions (2016-20) - General Principles and Processes of Isolation of Elements Notes | EduRev
Previous year Questions (2016-20) - General Principles and Processes of Isolation of Elements Notes | EduRev
Identify the correct statement:    (2016)
(1) At T > 1200 K, carbon will reduce MO(s) to M(s).
(2) At T < 1200 K, oxidation of carbon is unfavourable.
(3) Oxidation of carbon is favourable at all temperatures.
(4) At T < 1200 K, the reaction MO(s) + C(s) → M(s) + CO(g) is spontaneous.
Ans.
(4)
According to Ellingham diagram, as given
Previous year Questions (2016-20) - General Principles and Processes of Isolation of Elements Notes | EduRev
At T < 1200, carbon will reduce MO(s) to M(s).
Hence, chemical reaction C(s) + MO(s) → M(s) + CO(g) is spontaneous.

Q.26. Extraction of copper by smelting uses silica as an additive to remove:    (2016)
(1) FeS
(2) FeO
(3) Cu2S
(4) Cu2O
Ans.
(2)
Previous year Questions (2016-20) - General Principles and Processes of Isolation of Elements Notes | EduRev 

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