MCQ Questions for Class 12 Engineering Chemistry General Principles And Processes Of Isolation Of Elements Quiz 9

Metallurgy involves steps:

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Concentration of ore
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Reduction of ore
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Purification
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alloy formation

$ACl_2 +BCl_2 \longrightarrow ACl_4 +B \downarrow$
(Excess)

$BO\xrightarrow [ ]{ Heat } B+\dfrac12{ O }_{ 2 }$
(

$A$ and

$B$ are metals.)

Their ore of

$B$ is :

0%
cinnabar
0%
azurite
0%
galena
0%
siderite

Explanation

$ACl_2 +BCl_2 \longrightarrow ACl_4 +B \downarrow$
(Excess)

In this reaction, we can see that the oxidation number of A changes from +2 to +4. So, A should be Sn.

$BO\xrightarrow [ ]{ Heat } B+\dfrac12{ O }_{ 2 }$

The oxidation number of B changes from +2 to 0. B should be less reactive metal. So it is Hg. The ore of Hg is cinnabar.

Option (A) is correct.

Which of the following is correct processes ?

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$Fe+Al_2O_3 \longrightarrow 2Al +Fe_2O_3$
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$ZnO +C\longrightarrow Zn +CO$
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$Cr_2O_3 +2Al \longrightarrow 2Cr +Al_2O_3$
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$2[Ag(CN)_2]^- +Zn \longrightarrow 2Ag +[Zn (CN)_4]^{2-}$

Auto-reduction process is used for the extraction of :

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$Cu$
0%
$Hg$
0%
$Pb$
0%
$Al$

Consider the following statements :
Roasting is carried out to:
convert sulphide into oxide
melt the ore
remove moisture, water of hydration and expel organic matter
remove sulphur and arsenic in the form of volatile oxides
Out of these statements:

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$1, 3$ and $4$ are correct
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$1, 2$ and $3$ are correct
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$2, 3$ and $4$ are correct
0%
$1, 2$ and $4$ are correct

In Hall's process, the ore is mixed with

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coke
0%
calcium carbonate
0%
sodium hydroxide
0%
sodium carbonate

Explanation

Hall's process is used for the extraction of Aluminum from Alumina. Bauxite is concentrated through Hall’s process, in which sodium aluminate is prepared using sodium carbonate in bauxite. When excess carbon dioxide is passed through sodium aluminate in the presence of water, it forms aluminum hydroxide along with sodium carbonate. When dried aluminum hydroxide is ignited, alumina is formed.

The reaction involved in Hall's process is as follows:

$Al_2O_3.2H_2O+2Na_2CO_3→2NaAlO_2+CO_2+2H_2O$

Option D is correct.

Which of the following elements occurs in native state?

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$I$
0%
$S$
0%
$Si$
0%
$P$

The electrolytic reduction method for extraction of aluminium was discovered by:

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Hoope
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Hall and Halvoult
0%
Baeyer
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Serpeck

Explanation

The process of extracting Aluminium from Alumina

$Al_2O_3$ by electrolysis is called Hall-Heroult process. In this process Aluminium is produced at cathode which is obtained by outlet, oxygen is released at an anode. It reacts with carbon of anode producing

$CO$ and

$CO_2$

Hence, the correct option is (B).

Alumina is not used as

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refractory material
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a medium in chromatography
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abrasive
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a white pigment

Which of the following elements is /are present in the anode mud in electrolytic refining of copper?

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Selenium
0%
Tellurium
0%
Silver
0%
Gold

Explanation

In the electrolytic refining of copper, the anode mud contains antimony, selenium, tellurium, silver, gold and platinum. These are impurities in blister copper. They are less reactive and unaffected by

$CuSO_{4} - H_{2}SO_{4}$ solution and hence, settle down under anode as anode mud.

Hence, all options are correct.

Identify the correct statements:

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$FeSO_4.(NH_4)_2SO_4.6H_2O$ is called alum
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The mixture $NH_4NO_3 +Al$ powder is used as an explosive
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Anhydrous $AlCl_3$ is obtained when $HCl$ is passed over aluminum
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When $Al$ is heated with potassium hydroxide solution, hydrogen is evolved

Which of the following is not correctly matched?

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Red bauxite - Purification by Serpecks method.
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Iron from haematite - Carbon monoxide reduction
0%
Calamine - Carbonate ore
0%
$FeSiO_{3}$ - Slag obtained in the extraction of copper.

A substance which reacts with gangue to form fusible material is called

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Flux
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Catalyst
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Ore
0%
Slag

Explanation

(Impurity) Gangue + flux

$\rightarrow$ Slag

Infusible Fusible

Option A is correct.

In our country, iron is obtained from the ore:

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cassiterite
0%
azurite
0%
haematite
0%
cryolite

Which of the following metal is not found in free state

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$Na$
0%
$Au$
0%
$Ag$
0%
$Pb$

Explanation

$Na$ is alkali metal highly reactive. Hence present in combined state.

In froth floatation process, for the purification of ores, the particles of the ore float because:

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they are light
0%
they are insoluble
0%
they bear electrostatic charge
0%
their surface is not easily wetted by water

Naturally occurring substances from which a metal can be profitably (or economically) extracted are called

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Minerals
0%
Ores
0%
Gangue
0%
Salts

For which ore of the metal , forth floatation method is used for concentration

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Horn silver
0%
Bauxite
0%
Cinnabar
0%
Haematite

Explanation

Cinnabar

$(HgS)$ the ore of mercury is concentrated by froth floatation process.

The method of zone refining of metals is based on the principle of

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greater solubility of the impurity in the molten state than in the solid
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greater mobility of the pure metal than that of the impurity
0%
higher melting point of the impurity than that of the pure metal
0%
greater noble character of the solid metal than that of the impurity

Froth floatation process is used for concentration of

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Chalcopyrite
0%
Bauxite
0%
Haematite
0%
Calamine

Carbon monoxide reacts with iron to form

0%
$Fe(CO)_5$
0%
$FeCO_2$
0%
$FeO + C$
0%
$Fe_2O_3 +C$

Explanation

Carbon monoxide reacts with iron to form

$Fe_2O_3$ and

$C.$

$2Fe + 3CO \quad \xrightarrow {Heat} \quad Fe_2O_3 +3C$

General method for the extraction of metal from oxide ore is

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Carbon reduction
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Reduction by aluminium
0%
Reduction by hydrogen
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Electrolytic reduction

Explanation

Carbon reduction ,

$Fe_2O_3 + 3C \rightarrow 2 Fe + 3CO$

Which element is found in free state ?

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Iodine
0%
Sulphur
0%
Phosphorus
0%
Magnesium

Explanation

Among the following options, only Sulphur is found in its free state i.e.

$S_8$ .

Hence, Option "B" is the correct answer.

Write true or false for the following statements :
Those mineral which contain a very high percentage of a particular metal and from which metal can be profitably extracted are called ores.

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True
0%
False

Which occurs in nature in free state?

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Fe
0%
Co
0%
Ni
0%
Pt

Which one of the following is Fluorspar?

0%
$CaF_2$
0%
$CaO$
0%
$H_2F_2$
0%
$CaCO_3$

Explanation

$CaF_2$ is called Flourspar.

Hence, Option "A" is the correct answer.

The important step in the extraction of metal from carbonate ore is

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Calcination
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Roasting
0%
Electro - reduction
0%
Cupellation

Explanation

Calcination is an important in the extraction process

$ZnCO_3 \rightarrow ZnO + CO_2$

Option A.

Which of the following metals exist in their native state in nature?
(i)

$Cu$
(ii)

$Au$
(iii)

$Zn$
(iv)

$Ag$

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(i) and (ii)
0%
(ii) and (iii)
0%
(ii) and (iv)
0%
(iii) and (iv)

A mineral is usually associated with a large amount of unwanted material called :

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Gangue
0%
Flux
0%
Slag
0%
Ore

Which one of the following elements is most abundant is earth crust ?

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Aluminium
0%
Silicon
0%
Carbon
0%
Oxygen

Which one of the following types of metals is expected to occur in the native state ?

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The alkali metals
0%
The alkaline earth metal
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The noble metal
0%
The rare earth metals

Cinnabar is the ore of :

0%
Zn
0%
Cd
0%
Hg
0%
Ag

Highly electropositive metal (s) can not be commercially extracted by carbon reduction process at high temperature because these :

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metal combine with carbon to form covalent carbide
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metal combine with carbon to form ionic carbide
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$G_{f}$ of highly electropositive metal oxide is having low negative value
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Consider the following reaction at $1000^{0} C$

Three most occurring elements into the earth crust are :

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O ,Si,A1
0%
Si, O , Fe
0%
Fe , Ca , A1
0%
Si , O , N

Froth floatation process is used for the concentration of the ore of :

0%
Fe
0%
A1
0%
Cr
0%
Cu

In zone refining method , the molten zone :

0%
consist of impurities only
0%
contains more impurities than the original metal
0%
contains the purified metal only
0%
moves to either side

Which of thew following pair is correctly matched ?

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Copper - Oxidative refining
0%
Nickel - Kroll's process
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Mercury - Distillation
0%
Lead - van Arkel method

In which of the following metallurgy, no reduction agent is required from outside ?

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Mercury from cinnabar
0%
Zinc from zinc blende
0%
Iron from heamatite
0%
Aluminium from Bauxite

The method of zone refining of metals is based on the principle of :

0%
Greater mobility of the pure metal than that of impurity
0%
Higher melting point of the impurity than that of impurity
0%
Greater noble charcter of the solid meta than that of the pure metal
0%
Greater solubility of the impurity in the molten state than in the solid

Copper is extracted from sulphide ore using the method :

0%
carbon reduction
0%
carbon monoxide reduction
0%
auto reduction
0%
none of this

In the alumino-thermite process, Al metal acts as :

0%
Oxidizing agent
0%
Reducing agent
0%
Flux
0%
Gangue

Froth floatation process for the concentration of sulphide ores is an illustration of the practical application of :

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adsorption
0%
absorption
0%
sedimentation
0%
coagulation

The advantage of using carbon to reduce a number of oxides and other compounds are :

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easy availability of coke
0%
low cost of carbon
0%
tendency of carbon to show catenation
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presence of carbon lowers the melting point of the oxides

For which of following metals, the carbon reduction cannot be used

0%
Lead
0%
Manganese
0%
Tungsten
0%
Iron

The function of adding cryolite in the electrolytic reduction of alumina by Hall-Heroult process is to :

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dissolve alumina
0%
lower the melting point of alumina
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lower the fuel bill
0%
increase the electrical conductivity of alumina

The disadvantage of carbon reduction method are :

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high temperature needed is expensive and requires the use of a blast furnace
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many metals combine with carbon forming carbides
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Carbon combines with oxygen to form poisonous CO
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Carbon cannot be used with highly electropositive metals

Pick up the correct statement (S) :

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All minerals are ores
0%
All minerals cannot be an ore
0%
All ores are minerals
0%
The minerals from which can be extracted profitably are called ores

Froth floatation process is used to concentrate which type of ores?

0%
Sulphide ores
0%
Phosphate ores
0%
Silicate ores
0%
Oxide ores

The metal which always exists in free or native state is

0%
$Au$
0%
$Ag$
0%
$Cu$
0%
$Na$

Those natural occurring components from which element can be extracted profitably and conveniently known as

0%
Minerals
0%
Gangue
0%
Ores
0%
Flux

CBSE Questions for Class 12 Engineering Chemistry General Principles And Processes Of Isolation Of Elements Quiz 9 - MCQExams.com

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Practice Class 12 Engineering Chemistry Quiz Questions and Answers

CBSE Questions for Class 12 Engineering Chemistry General Principles And Processes Of Isolation Of Elements Quiz 9 - MCQExams.com

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Practice Class 12 Engineering Chemistry Quiz Questions and Answers

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