Ores and Metallurgy MCQ Questions & Answers in Inorganic Chemistry | Chemistry
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11.
Fill in the blanks with the correct choice.
The undesired impurities present in the ores are called $$\underline {\left( {\text{i}} \right)} .$$ To remove the volatile impurities from the ore, the $$\underline {\left( {{\text{ii}}} \right)} $$ process is carried out. Flux combines with non-fusible impurities to form $$\underline {\left( {{\text{iii}}} \right)} .$$ $$CaO$$ acts as a $$\underline {\left( {{\text{iv}}} \right)} $$ flux.
(i)
(ii)
(iii)
(iv)
(a)
gangue
roasting
slag
acidic
(b)
gangue
calcination
Slag
basic
(c)
anode mud
leaching
matrix
acidic
(d)
gangue
roasting
solution
acidic
A
(a)
B
(b)
C
(c)
D
(d)
Answer :
(b)
No explanation is given for this question. Let's discuss the answer together.
12.
The ore that contains both iron and copper is:
A
copper pyrites
B
malachite
C
dolomite
D
azurite
Answer :
copper pyrites
Amongst the given ores, copper pyrite $$\left( {CuFe{S_2}} \right),$$ dolomite $$\left( {MgC{O_3}.CaC{O_3}} \right),$$ malachite $$\left[ {CuC{O_3}.Cu{{\left( {OH} \right)}_2}} \right],$$ azurite $$\left[ {2CuC{O_3}.Cu{{\left( {OH} \right)}_2}} \right],$$ copper pyrite contains both copper and iron.
13.
Extraction of zinc from zinc blende is achieved by
A
roasting followed by self-reduction
B
electrolytic reduction
C
roasting followed by reduction with carbon
D
roasting followed by reduction with another metal
Answer :
roasting followed by reduction with carbon
Extraction of $$Zn$$ from zinc blends is achieved by roasting followed by reduction with carbon. Reactions involved are :
\[\begin{align}
& 2ZnS+3{{O}_{2}}\xrightarrow{\text{heat}}2ZnO+2S{{O}_{2}}\text{(Roasting)} \\
& ZnO+C\text{(Coke)}\xrightarrow{\text{heat}}Zn+CO\text{(Reduction)} \\
\end{align}\]
14.
Aluminium is extracted by the electrolysis of
A
bauxite
B
alumina
C
alumina mixed with molten cryolite
D
molten cryolite.
Answer :
alumina mixed with molten cryolite
Pure aluminium can be obtained by electrolysis of a mixture containing alumina, crayolite and fluorspar in the ratio 20 : 24 : 20. The fusion temperature of this mixture is $${900^ \circ }C$$ and it is a good conductor of electricity.
15.
Find the incorrect match.
A
Fine dust of aluminium - Paints and Lacquers
B
Reducing agent in the manufacture of dye-stuffs, paints, etc. - Copper dust
C
For cutting tools and crushing machines - Chrome steel
D
For making cables, automobiles and aeroplane parts - Nickel steel
Answer :
Reducing agent in the manufacture of dye-stuffs, paints, etc. - Copper dust
Zinc dust is used as a reducing agent in the manufacture of dye-stuffs, paints, etc.
16.
Electrolytic refining is used to purify which of the following metals?
A
$$Cu\,\,{\text{and}}\,Zn$$
B
$$Ge\,\,{\text{and}}\,\,Si$$
C
$$Zr\,\,{\text{and}}\,\,Ti$$
D
$$Zn\,\,{\text{and}}\,\,Hg$$
Answer :
$$Cu\,\,{\text{and}}\,Zn$$
No explanation is given for this question. Let's discuss the answer together.
17.
In electro-refining of copper, some gold is deposited as
A
cathode mud
B
electrolyte
C
anode mud
D
cathode
Answer :
anode mud
In electro-refining of copper, the zinc, nickel and iron remain in the solution, while gold is deposited as anode mud. The anode decreases in weight gradually.
18.
Which of the following metals is extracted by the electrometallurgical method ?
A
$$Cu$$
B
$$Fe$$
C
$$Na$$
D
$$Ag$$
Answer :
$$Na$$
$$Na$$ is obtained by elctrolytic reduction being electropositive in nature.
19.
Copper can be extracted from
A
Kupfernical
B
Dolomite
C
Malachite
D
Galena
Answer :
Malachite
Malachite is $$CuC{O_3}\,.\,Cu{\left( {OH} \right)_2}$$ it is ore of copper.
20.
Match items of Column I with the items of Column II and assign the correct code.
Column I
Column II
a.
Cyanide process
1.
Ultrapure $$Ge$$
b.
Froth floatation process
2.
Dressing of $$ZnS$$
c.
Electrolytic reduction
3.
Extraction of $$Al$$
d.
Zone refining
4.
Extraction of $$Au$$
5.
Purification of $$Ni$$
A
a - 2, b - 3, c - 1, d - 5
B
a - 1, b - 2, c - 3, d - 4
C
a - 3, b - 4, c - 5, d - 1
D
a - 4, b - 2, c - 3, d - 1
Answer :
a - 4, b - 2, c - 3, d - 1
$$A - 4,\,B - 2,\,C - 3,\,D - 1$$
$$ \bullet $$ Cyanide process It is a metallurgical technique for extracting $$Au$$ (gold) from low grade ore by corverting the $$Au$$ to a water-soluble coordination complex.
$$ \bullet $$ Froth floatation process This process is used for dressing of sulphide ore, i.e. $$ZnS.$$
$$ \bullet $$ Electrolytic reduction This process is used for extraction of $$Al$$ which is carried out in a steel tank lined inside with graphite. Here, graphite serves as cathode. The electrolyte consists of alumina dissolved in fused cryolite $$\left( {N{a_3}Al{F_6}} \right)$$ and fluorspar $$\left( {Ca{F_2}} \right).$$
$$ \bullet $$ Zone refining This process is used for ultra pure $$Ge$$ element. An ingot of $$Ge$$ is first purified by zone refining. Then a small amount of antimony is placed in the molten zone which is passed through the pure $$Ge$$ with the proper choice of rate of heating and other variables.