Test: Extraction Of Crude Metals From Concentrated Ores


25 Questions MCQ Test Chemistry Class 12 | Test: Extraction Of Crude Metals From Concentrated Ores


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This mock test of Test: Extraction Of Crude Metals From Concentrated Ores for Class 12 helps you for every Class 12 entrance exam. This contains 25 Multiple Choice Questions for Class 12 Test: Extraction Of Crude Metals From Concentrated Ores (mcq) to study with solutions a complete question bank. The solved questions answers in this Test: Extraction Of Crude Metals From Concentrated Ores quiz give you a good mix of easy questions and tough questions. Class 12 students definitely take this Test: Extraction Of Crude Metals From Concentrated Ores exercise for a better result in the exam. You can find other Test: Extraction Of Crude Metals From Concentrated Ores extra questions, long questions & short questions for Class 12 on EduRev as well by searching above.
QUESTION: 1

Only One Option Correct Type

Direction (Q. Nos. 1-10) This section contains 10 multiple choice questions. Each question has four choices (a), (b), (c) and (d), out of which ONLY ONE is correct.

Q.

Which of the following is not correctly matched ?

Solution:

Cyanide process The extraction of gold from its ores by dissolving the gold in a solution of potassium cyanide, KCN. The resulting potassium aurocyanide, KAu(CN)2, with zinc, filtering off, melting down and cupelling the metal.

*Multiple options can be correct
QUESTION: 2

The purpose of adding cryolite is

Solution:

Cryolite is used in the electrolysis of aluminium oxide. The mixture of cryolite and aluminium oxide has a lower melting point than pure aluminium oxide. This means a lower amount of energy is required to establish effective conditions for electrolysis and thus makes it more cost effective.

Fluorspar is added along with cryolite as electrolytes with Gibbsite fluorspar is responsible for increasing the conductivity as well as the fluidity of Al whereas cryolite lowers the melting point of Al2O3

Hence the correct answers are A and B.

QUESTION: 3

In Mac Arthur Forest method, silver is extracted from the solution of Na[Ag(CN)2] by the use of

Solution:

QUESTION: 4

In the extraction of copper, the metal formed in the Bessem er’s convertor is due to the reaction

Solution:

Some times the sulphide ore may be oxidised to sulphate which is then reduced to the free metal by the excess of the sulphide ore.

QUESTION: 5

The nitrate of which metal leaves metallic globule on strongly heating ?

Solution:

The nitrate of AgNO3 leaves metallic globule on strongly heating.

QUESTION: 6

In the extraction of gold, the cyanide solution acts as a

Solution:

When the gold pass in to the solution of sodium or potassium cyanide forming the respective soluble complex cyanides while the impurities remain unaffected which are filtered off.

QUESTION: 7

The matte is impure substance obtained during the extraction of

Solution:

The suphide ores of copper are heated in reverberatory furnace. If the ore contains iron. It is mined with silica before heating. Iron oxide slags of as iron silicate and copper produced in the form of copper matte , which contain Cu2S and FeS.

QUESTION: 8

During the extraction of gold the following reactions takes place
  Au + CN- + H2 X,

X + Zn → Y + Au

Solution:


QUESTION: 9

Identify the reaction that does not take place in a blast furnace

Solution:

Iron is produced by the following reaction.
FeO + C → Fe + CO

QUESTION: 10

Roasting of sulphides gives the gas X as a byproduct. This is a colourless gas with choking smell of burnt sulphur and causes great damage to respiratory organs as a result of acid rain. Its aqueous solution is acidic, acts as reducing agent and its acid is never isolated. The gas X is

Solution:

The reactions involve in roasting process.
2ZnS + 3O2 → 2ZnO + 2SO2
2PbS + 3O2 → 2PbO + 2SO2
2Cu2S + 3O2 → 2Cu2O + 2SO2
The SO2 produced is utilised for manufacturing H2SO4.

*Multiple options can be correct
QUESTION: 11

One or More than One Options Correct Type

Direction (Q. Nos. 11-15) This section contains 5 multiple choice questions. Each question has four choices (a), (b), (c) and (d), out of which ONE or MORE THAN ONE are correct.

Q. 

In the following processes, which are not sulphatising roasting ?

Solution:

22ZnS + 3O2 → 2ZnO + 2SO2,
2CU2S + 3O2 → 2Cu2O + 2SO2
Ag2S + 2NaCI + O2 → 2AgCI + Na 2SO4

QUESTION: 12

In the extraction of copper from its sulphide ore, the metal is finally obtained by the reduction of cuprous oxide with

Solution:

n the extraction of copper from its sulphide ore, when ore is subjected to roasting, some of it is oxidised to Cu2O which reacts with the remaining Cu2S (sulphide ore) to give copper metal.
Cu2S +2Cu2O → 6Cu +SO2 ↑
In this process, Cu2S behaves as reducing agent. 

*Multiple options can be correct
QUESTION: 13

Which is correctly matched?

Solution:

Pyrometallurgy = Fe, Zn and Cu
Electrometallurgy = Al, Mg and Na
Hydrometallurgy = Ag and Au

*Multiple options can be correct
QUESTION: 14

Which of tlfe following metal sulphides are converted into metals by self reduction?

Solution:

Self reduction or auto-reduction or self electronation


*Multiple options can be correct
QUESTION: 15

Which of the following are correct process ?

Solution:

The process of reduction of metal oxide to the metal with the help of aluminium powder as the reducing agent is called Goldschmidt thermite process.
2AI + Fe2O3 → Al2O3 + 2Fe

QUESTION: 16

Comprehension Type

Direction (Q. Nos. 16 and 17) This section contains a paragraph, describing theory, experiments, data, etc. Two questions related to the paragraph have been given. Each question has only one correct answer among the four given options (a), (b), (c) and (d).

Passage

Copper is extracted from copper pyrites. After roasting, the ore is mixed with silica and coke and then smelted in a blast furnace. The matte obtained from the blast furnace is charged into silica lined convertor. Some silica is also added and a hot air blast is blown into the mixture to obtain blister copper which is purified by electro refining.

Q. 

The chemical formula of copper pyrites is

Solution:

Copper pyrites is CuFeS2. Copper can be extracted from this by roasting of sulphide partially and reduction.

QUESTION: 17

Copper is extracted from copper pyrites. After roasting, the ore is mixed with silica and coke and then smelted in a blast furnace. The matte obtained from the blast furnace is charged into silica lined convertor. Some silica is also added and a hot air blast is blown into the mixture to obtain blister copper which is purified by electro refining.

Q. 

Coke is added during smelting

Solution:

Carbon (coal or coke) reduces the metal oxide to the free metal, e.g.

The carbon monoxide obtained by the incomplete combustion of carbon can also bring about the reduction of metal oxides to free metal. e.g.

QUESTION: 18

Matching List Type

Direction (Q. Nos. 18 and 19) Choices for the correct combination of elements from Column I and Column II are given as options (a), (b), (c) and (d), out of which one is correct.

Q. 

Match the Column I with Column II and mark the correct option from the codes given below.

Solution:

(i) → (q), (ii) → (s), (iii) → (r), (iv) → (p)
Low electropositive metal oxides like Fe2O3 and ZnO can be reduced by CO. Cr2O3 cannot be reduced by CO or C because of their high melting point, some metal sulphides self reduced during roasting like CU2S, PbS and HgS.

QUESTION: 19

Match the Column I with Column II and mark the correct option from the codes given below.

Solution:

(i) → (r), (ii) → (p,t), (iii) → (q), (iv) → (s)

*Answer can only contain numeric values
QUESTION: 20

One Integer Value Correct Type

Direction (Q. Nos. 20-24) This section contains 5 questions. When worked out will result is an integer from 0 to 9 (both inclusive)

Q. 

Among Ca, Pb, Sn, Ag, Mg, Au, Zn, Cu, Al, Na, Hg the number of metals extracted by pyrometallurgy are


Solution:

Pyrometallurgy It is a branch of extractive metallurgy. It involves the thermal treatment of minerals and metallurgical ores and concentrates to bring about physical and chemical transformation in the materials to enable recovery of valuable metals.
It include the extraction of oxide of less reactive elements like, Pb, Sn, Zn and Cu.

*Answer can only contain numeric values
QUESTION: 21

Among Ca, Pb, Sn, Ag, Mg, Au, Zn, Cu, Al, Na, Hg, K, the number of metals extracted by electrometallurgy are


Solution:

Pb, Ag, Au, Zn, Cu, Al, Electrometallurgy is the process of extraction of metals by electrolysis of their fused salt.

*Answer can only contain numeric values
QUESTION: 22

 in this how many CN- ions are involved in the balanced equation?


Solution:

4Au + 8CN- + 2H2O + O2 → 4[Au(CN)2]- + 4OH-

*Answer can only contain numeric values
QUESTION: 23

In the electrolytic extraction of Al at cathode Al metal and at anode F2 gas is liberated. If the molar ratio of Al and F2 is 2 : x, here value of is x


Solution:

The molar ratio of Al and F2 is 2 : 3.

*Answer can only contain numeric values
QUESTION: 24

In Goldschmidt alum inothermic process, therm it mixture contains ...... parts Fe2O3 and one part Al powder.


Solution:

In thermite mixture contains 3 parts of Fe2O3 and one part of Al.

QUESTION: 25

Statement Type

Direction (Q. No. 25) This section is based on Statement I and Statement II. Select the correct answer from the codes given below.

Q. 

Statement I : Cast iron is obtained by remelting pig iron with scrap iron and coke wing hot air blast.
Statement II : In the extraction of silver, silver is extracted as cationic complex.

Solution:

Cast iron is obtained by remelting pig iron with scrap iron and coke using hot air blast.
In the extraction of silver, silver is extracted as anionic complex [Ag(CN)2],