Ores and Metallurgy MCQ Questions & Answers in Inorganic Chemistry | Chemistry
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131.
Most electropositive metals are obtained from their ores by
A
auto-reduction
B
smelting with carbon
C
electrolysis of fused salts
D
thermal decomposition
Answer :
electrolysis of fused salts
No explanation is given for this question. Let's discuss the answer together.
132.
Which ore contains both iron and copper?
A
Cuprite
B
Chalcocite
C
Chalcopyrite
D
Malachite
Answer :
Chalcopyrite
Cuprite: $$\,Cu{O_2};$$ Chalcocite : $$C{u_2}S;$$ Chalcopyrite : $$CuFe{S_2};$$
Malachite: $$Cu{\left( {OH} \right)_2}.CuC{O_3}.$$ We see that $$CuFe{S_2}\,$$ contais both $$Cu\,{\text{and}}\,Fe.$$
133.
Cryolite is
A
$$N{a_3}Al{F_6}$$ and used in the electrolysis of alumina for decreasing electrical
conductivity
B
$$N{a_3}Al{F_6}$$ and used in the electrolysis of alumina for lowering the melting point of alumina
C
$$N{a_3}Al{F_6}$$ and used in the electrolytic purification of alumina
D
$$N{a_3}Al{F_6}$$ and used in the electrolysis of alumina
Answer :
$$N{a_3}Al{F_6}$$ and used in the electrolysis of alumina for lowering the melting point of alumina
$$N{a_3}Al{F_6}$$ is cryolite and used in the electrolysis of alumina to lower the melting point and increase electrical conductivity.
134.
Match the column I with column II and mark the appropriate choice.
Column I
Column II
a.
Highly electropositive metals
1.
Carbon reduction
b.
Copper
2.
$$CO$$ reduction
c.
Iron
3.
Self reduction
d.
Zinc
4.
Electrolysis
A
a - 4, b - 3, c - 2, d - 1
B
a - 3, b - 2, c - 1, d - 4
C
a - 2, b - 1, c - 3, d - 4
D
a - 1, b - 2, c - 3, d - 4
Answer :
a - 4, b - 3, c - 2, d - 1
No explanation is given for this question. Let's discuss the answer together.
135.
In the extraction of copper from its sulphide ore, the metal finally obtained by the reduction of cuprous oxide with
A
iron (II) sulphide
B
carbon monoxide
C
copper (I) sulphide
D
sulphur dioxide
Answer :
copper (I) sulphide
$$C{u_2}S + 2C{u_2}O \to 6Cu + S{O_2} \uparrow $$
136.
The powdered ore is agitated with water or washed with running stream of water. The heavy ore particles and lighter impurities are separated. This method of concentration is known as
A
metallurgy
B
leaching
C
gravity separation
D
froth floatation process
Answer :
gravity separation
No explanation is given for this question. Let's discuss the answer together.
137.
Which of the following changes take place during roasting?
(i) Impurities are removed as their volatile oxides.
(ii) Ore is converted into its oxide.
(iii) Changes like oxidation, chlorination, etc. take place.
A
(i) and (ii)
B
(ii) and (iii)
C
(i) and (iii)
D
(i), (ii) and (iii)
Answer :
(i), (ii) and (iii)
No explanation is given for this question. Let's discuss the answer together.
138.
Which of the following examples is not correctly matched?
A
Two most abundant elements - $$ Fe,Al$$
B
Two metals which occur in native state - $$ Au,Pt$$
C
Two metals which can occur in combined and native state both - $$ Zn,Fe$$
D
None of these
Answer :
Two metals which can occur in combined and native state both - $$ Zn,Fe$$
$$Zn$$ and $$Fe$$ occur only in combined state.
139.
In the context of the Hall - Heroult process for the extractionof $$Al,$$ which of the following statements is false?
A
$$A{l^{3 + }}$$ is reduced at the cathode to form $$Al$$
B
$$N{a_3}Al{F_6}$$ serves as the electrolyte
C
$$CO$$ and $$C{O_2}$$ are produced in this process
D
$$A{l_2}{O_3}$$ is mixed with $$Ca{F_2}$$ which lowers the melting point of the mixture and brings conductivit $$119y$$
Answer :
$$N{a_3}Al{F_6}$$ serves as the electrolyte
In the metallurgy of aluminium, purified $$A{l_2}{O_3}$$ is mixed with $$N{a_3}Al{F_6}\,\,{\text{or}}\,\,Ca{F_2}$$ which lowers the melting point of the mix and brings conductivity.
140.
The method of zone refining of metals is based on the principle of :
A
Greater solubility of the impurity in the molten state than in the solid
B
Greater mobility of the pure metal than that of the impurity
C
Higher melting point of the impurity than that of the pure metal
D
Greater noble character of the solid metal than that of the impurity
Answer :
Greater solubility of the impurity in the molten state than in the solid
Zone refining is based on the difference in solubility of impurities in molten and solid state of the metal. This method is used for obtaining metals of very high purity.