Ores and Metallurgy MCQ Questions & Answers in Inorganic Chemistry | Chemistry
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111.
Sometimes it is possible to separate two sulphide ores by adjusting the proportion of oil to water or by using depressants. When a depressant $$NaCN$$ is added to an ore containing $$ZnS$$ and $$PbS,$$ what is the correct observation?
A
$$NaCN$$ prevents $$PbS$$ from coming to the froth but allows $$ZnS$$ to come with froth.
B
$$NaCN$$ prevents $$ZnS$$ from coming to the froth but allows $$PbS$$ to come with froth.
C
$$NaCN$$ prevents frothing of both $$ZnS$$ and $$PbS,$$ hence no froth is formed.
D
$$NaCN$$ does not act as depressant hence a mixture of $$PbS$$ and $$ZnS$$ is found in froth.
Answer :
$$NaCN$$ prevents $$ZnS$$ from coming to the froth but allows $$PbS$$ to come with froth.
No explanation is given for this question. Let's discuss the answer together.
112.
Sulfide ores are common for the metals
A
$$Ag,Cu\,\,{\text{and}}\,Pb$$
B
$$Ag,\,Mg\,\,{\text{and}}\,Pb$$
C
$$Ag,\,Cu\,\,{\text{and}}\,Sn$$
D
$$Al,\,Cu\,\,{\text{and}}\,Pb$$
Answer :
$$Ag,Cu\,\,{\text{and}}\,Pb$$
Silver, copper and lead are commonly found in earth's crust as $$A{g_2}S$$ (silver glance), $$CuFe{S_2}$$ (copper pyrites)
and $$PbS$$ (galena)
113.
Which of the following metal is leached by cyanide process
A
$$Ag$$
B
$$Na$$
C
$$Al$$
D
$$Cu$$
Answer :
$$Ag$$
$$Ag$$ is leached by cyanide process.
114.
In electro-refining of metal the impure metal is made the anode and a strip of pure metal, the cathode, during the electrolysis of an aqueous solution of a complex metal salt. This method cannot be used for refining of
A
silver
B
copper
C
aluminium
D
sodium
Answer :
sodium
Na reacts vigorously with water ( exothermic process )
115.
In the isolation of metals, calcination process usually results in :
A
metal hydroxide
B
metal sulphide
C
metal oxide
D
metal carbonate
Answer :
metal oxide
Calcination is the process of converting an ore into its oxide by heating it strongly below its melting point either in absence or limited supply of air. It is usually done to convert metal carbonates and hydroxides to their respective oxides.
\[\begin{align}
& \underset{\text{Limestone}}{\mathop{CaC{{O}_{3}}}}\,\xrightarrow{\Delta }\underset{\begin{smallmatrix}
\text{Calcium} \\
\,\,\,\text{oxide}
\end{smallmatrix}}{\mathop{CaO}}\,+C{{O}_{2}}\uparrow \\
& CuC{{O}_{3}}.Cu{{\left( OH \right)}_{2}}\xrightarrow{\Delta }2CuO+{{H}_{2}}O\uparrow +C{{O}_{2}} \\
\end{align}\]
116.
Cassiterite is an ore of
A
$$Mn$$
B
$$Ni$$
C
$$Sb$$
D
$$Sn$$
Answer :
$$Sn$$
Cassiterite is an ore of $$Sn,$$ its chemical composition is $$Sn{O_2}.$$ It is also known as tin stone.
117.
Which of the following pairs of metals is purified by van-Arkel method?
A
$$Zr\,\,{\text{and}}\,\,Ti$$
B
$$Ag\,\,{\text{and}}\,\,Au$$
C
$$Ni\,\,{\text{and}}\,\,Fe$$
D
$$Ga\,\,{\text{and}}\,\,In$$
Answer :
$$Zr\,\,{\text{and}}\,\,Ti$$
$$Zr$$ and $$Ti$$ are purified by van-Arkel method.
\[\underset{\text{Impure}}{\mathop{Zr}}\,+2{{I}_{2}}\xrightarrow{600{{\,}^{\circ }}C}Zr\,{{I}_{4}}\xrightarrow{1800{{\,}^{\circ }}C}\underset{\text{Pure}}{\mathop{Zr}}\,+2\,{{I}_{2}}\]
This method is useful for removing all the oxygen and nitrogen present in the form of impurity in certain metals like $$Zr$$ and $$Ti.$$
118.
An ore of tin containing, $$FeCr{O_4}$$ is concentrated by
A
gravity separation
B
magnetic separation
C
froth floatation
D
leaching
Answer :
magnetic separation
$$FeCr{O_4}$$ is magnetic and tin is non-magnetic hence it can be separated by magnetic separation.
119.
Purification of aluminium by electrolytic refining is known as
A
Hall’s process
B
Baeyer's process
C
Hoope's process
D
Serpeck's process
Answer :
Hoope's process
Purification of aluminium by electrolytic refining is known as Hoope’s process. By this process 99.9% pure aluminium metal is obtained. The cell used for this process consist of three layers. In this cell pure $$Al$$ acts as cathode and anode is made up of impure $$Al.$$
120.
Which of the following is magnetite?
A
$$F{e_2}C{O_3}$$
B
$$F{e_2}{O_3}$$
C
$$F{e_3}{O_4}$$
D
$$F{e_2}{O_3} \cdot 3{H_2}O$$
Answer :
$$F{e_3}{O_4}$$
No explanation is given for this question. Let's discuss the answer together.