Isolation of Elements Test 11

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Isolation of Elements Test 11

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Weekly Quiz Competition

Question 1
1 / -0

Which of the following statements is incorrect?

A
calamine and siderite are carbonates

B
malachite and azurite are ores of copper

C
zinc blende and pyrites are sulphides.

D
argentite and cuprite are oxides

Solution

Statement : Zinc blende and iron pyrites are sulphides. This statement is correct because zinc blende is ZnS and iron pyrites is FeS2. Statement : Calamine and siderite are carbonates. This statement is correct because calamine is ZnCO₃ and siderite is FeCO₃. Statement : Malachite and azurite are ores of copper. This statement is also correct because malachite is Cu(OH)₂.CuCO₃ and azurite isCu(OH)₂.2CuCO₃. Statement : Argentite and cuprite are oxides. This statement is incorrect because argentite is Ag₂S and cuprite is Cu₂O.
Question 2
1 / -0

Match the column (I) and (II) and select the correct answer using the codes given below.

A

B

C

D

Solution
Question 3
1 / -0

Select the correct statement.

A
In the decomposition of an oxide into oxygen and gaseous metal, entropy increases.

B
Decomposition of an oxide is an endothermic change.

C
To make ΔGo negative, temperature should be high enough so that TΔSo > ΔHo.

D
All are correct statements

Solution

(A),(B) and (C) stat4ements are correct.
Question 4
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NaCN is sometimes added in the froth floatation process as a depressant when mineral contains ZnS and PbS because,

A
Pb(CN)₂ is precipitated while there is no effect of ZnS.

B
ZnS forms soluble complex Na₂[Zn(CN)₄] while PbS forms froth.

C
PbS forms soluble complex Na₂[Pb(CN)₄] while ZnS forms froth.

D
silicious impurities settle down on the bottom.

Solution
Question 5
1 / -0

Which does not represent correct method?

A
TiCl_{2 +}2Mg → Ti +2MgCl₂ : Kroll

B
Ni(CO)₄→ Ni + 4CO : Mond

C
Ag₂CO₃ → 2Agc + CO₂ + 1/2O₂ : Van Arkel

D
Zrl₄ → Zr + 2I₂ : Van Arkel

Solution

This process is si,ply calcination.
Question 6
1 / -0

Main source of lead is galena (PbS). It is converted to Pb by :
(A) :
(B)

A
A

B
B

C
both

D
none

Solution

PbS reduces PbO to Pb and SO₂ is liberaated. This is called as self reduction.
Question 7
1 / -0

For which of the following metals Bessemerisation process is important?
I : Fe, II : Cu, III : Al, IV : Silver :

A
I, II

B
II , III

C
I, III

D
all

Solution

I = In manufacture os steel, II + Self reductio of Cu2O to Cu O to Cu vby CuS
Question 8
1 / -0

The chemical processes in the production of steel from haematite ore involve:

A
Reduction

B
Oxidation

C
Oxidation followed by reduction

D
Reduction followed by oxidation

Solution

Firstly, carbon which is added along which crushed haematite ore is oxidised to CO(andCO2) and second the produced CO acts as chief reducing agent for the reduction of haematite to steel.
Question 9
1 / -0

The chemical composition of 'slag' formed during the smelting process in the extraction of copper is

A
Cu₂ + FeS

B
FeSiO₃

C
CuFeS₂

D
Cu₂S + FeO

Solution
Question 10
1 / -0

Which of the following statement is incorrect about the extractive metallurgy of copper?

A
Matte chiefly consists of cuprous sulphide and some ferrous sulphide.

B
Most of the impurity of iron sulphide is removed as fusible slag during roasting.

C
The copper pyrites is concentrated by froth floatation process.

D
self reduction and electrolysis respectively

Solution
Question 11
1 / -0

Pb and Sn are extracted from their chief ore by:

A
carbon reduction and self reduction respectively.

B
self reduction and carbon reduction respectively.

C
electrolysis and self reduction respectively.

D
self reduction and self reduction respectively

Solution
Question 12
1 / -0

Which of the following statements is incorrect?

A
Cassiterite ore of tin contains the impurities of Wol-framite which are separated by electromagnetic separator.

B
Tin metal is obtained by the carbon reduction of black tin.

C
In the extraction of lead from galena, the roasting and self-reduction are carried in the same furnace at different temperatures.

D
Reducing agent of haematite in blast-furnace is coke in upper part and CO in lower part of furnace.

Solution
Question 13
1 / -0

Which of the following process is used in the extractive metallurgy of magnesium?

A
Fused salt electrolysis

B
Self reduction

C
Aqueous solution electrolysis

D
Thermite process.

Solution
Question 14
1 / -0

White bauxite is purified by :

A
Baeyer’s process

B
Hoop’s process

C
Serpeck’s process

D
Hall’s process

Solution

White bauxite containing the impurity of silica only in removed by heating with coke in atmosphere of nitrogen.
Question 15
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Which of the following statements is correct?

A
In Hall-Heroult process, the electrolyte used is a molten mixture of alumina, sodium hydroxide and cryolite.

B
Lead is extracted form its chief ore by both carbon reduction and self reduction.

C
Tin is extracted from its chief ore by carbon monoxide reduction.

D
Siderite, cassiterite and argentite are carbonate ores

Solution
Question 16
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Statement-1 : The reduction of a metal oxide is easier if the metal formed is in liquid state at the temperature of reduction.
Statement-2 : The value of entropy change +S of the reduction process is more on +ve side when the metal formed is in liquid state and the metal oxide being reduced is in solid state. Thus the value of +Go becomes more on negative side.

A
Statement- 1 is True, Statement- 2 is True; Statement- 2 is a correct explanation for Statement- 1.

B
Statement- 1 is True, Statement- 2 is True; Statement- 2 is NOT a correct explanation for Statement-1.

C
Statement- 1 is True, Statement- 2 is False.

D
Statement- 1 is False, Statement- 2 is True.

Solution

Randomness increases on changing the phase from soilid to liqid or from liquid to gas
Question 17
1 / -0

Statement- 1: Extraction of gold from its native ore involves leaching the metal with dilute solution of NaCN in presence of air.
Statement-2 : This is an oxidation reaction and leads to the formation of a soluble comoplex.

A
Statement- 1 is True, Statement- 2 is True; Statement- 2 is a correct explanation for Statement-1.

B
Statement- 1 is True, Statement- 2 is True; Statement- 2 is NOT a correct explanation for Statement-1.

C
Statement- 1 is True, Statement- 2 is False.

D
Statement- 1 is False, Statement- 2 is True

Solution
Question 18
1 / -0

Statement- 1: Silica is added as a flux in reverberatory furnace, in the extraction of copper from copper pyrites.
Statement-2 : Silica decreases the melting point of the ore and remove the impurity of lead sulphide as PbSiO3.

A
Statement- 1 is True, Statement- 2 is True; Statement- 2 is a correct explanation for Statement-1.

B
Statement- 1 is True, Statement- 2 is True; Statement- 2 is NOT a correct explanation for Statement-1.

C
Statement- 1 is True, Statement- 2 is False.

D
Statement- 1 is False, Statement- 2 is True.

Solution
Question 19
1 / -0

Statement- 1: Cast iron is different from pig iron.
Statement-2 : Cast iron is made by melting pig iron with scrap iron and coke using hot air blast and has about 3% carbon content.

A
Statement- 1 is True, Statement- 2 is True; Statement- 2 is a correct explanation for Statement-1.

B
Statement- 1 is True, Statement- 2 is True; Statement- 2 is NOT a correct explanation for Statement-1.

C
Statement- 1 is True, Statement- 2 is False.

D
Statement- 1 is False, Statement- 2 is True.

Solution

Cast iron contains 3% carbon.
Question 20
1 / -0

Statement- 1: In the Hoop’s process of aluminium purification, the fused materials remain in three different layers. These layers remain intact even in electrolytic reduction.
Statement-2 : This is an oxidation reaction and leads to the formation of a soluble complex.

A
Statement- 1 is True, Statement- 2 is True; Statement- 2 is a correct explanation for Statement-1.

B
Statement- 1 is True, Statement- 2 is True; Statement- 2 is NOT a correct explanation for Statement-1.

C
Statement- 1 is True, Statement- 2 is False

D
none of these

Solution